SEC(2007) 468

COMMISSION STAFF WORKING DOCUMENT

REPORT OF THE SCIENTIFIC, TECHNICAL AND ECONOMICCOMMITTEE FOR FISHERIES EVALUATION OF THE REPORT OF THE STECF-SGRST 06-03 WORKING GROUP ON ANGLERFISH STECF undertook this evaluation by correspondence in June-July 2006

This report does not necessarily reflect the view of the European Commission and in no way anticipates the Commission’s future policy in this area

Background

There are major uncertainties about catch and effort data for anglerfish ( Lophius piscatorius ), as well as limited knowledge about population dynamics and distribution. In addition, existing surveys have not proven useful in describing the population. In this situation, a two-stage approach has been advised. The first stage would be to substantially improve the quality and quantity of data collected on the fishery while maintaining exploitation at its current level, followed by a second stage of better informed advice and management.

Following this two-step approach, the fishing mortality experienced by anglerfish in the North Sea and West of Scotland should not increase until conclusive evidence is presented on an acceptable exploitation level. STECF has recommended that anglerfish fisheries in divisions IV and VI should be continued while not permitting an increase in fishing effort. STECF has not yet been able to recommend operational methods for implementing such a limitation. While such a system is being developed, there is a requirement for an in-year adaptation of the TAC in line with a status-quo fishing mortality.

An STECF SGRST 06-03 Working group was convened from 24-27 April 2006 in Brussels to address the following Terms of Reference:

1. Identify criteria for the management of anglerfish fisheries using effort management as the primary conservation instrument. The sub-group is requested to:

a. Identify, in terms of characteristics of fishing vessels, the gears they use and the areas and seasons in which they operate, the main fishing métiers that catch anglerfish in the North Sea and West of Scotland.

b. For each sector identified in (a), quantify the catches of anglerfish and of other species caught in the same fishing operations.

c. For each the sector identified in (a), provide details of historic effort deployed in each fishery, disaggregated by gear type and by Member State, for the longest available time-series.

2. Advise on a TAC for anglerfish in ICES areas IV and VI that is consistent with (a) no increase in fishing mortality or fishing effort on this species, (b) available information on commercial catch rates.

The Working Group report is attached as Annex 1.

Review of the SGRST 06-03 Working Group report

STECF reviewed the report of the 3rd STECF_SGRST (SGRST 06-03) meeting on anglerfish by correspondence during June-July 2006.

The SGRST 06-03 Working Group summarized its findings as follows:

The fishery for anglerfish ( Lophius piscatorius ) in the North Sea and West of Scotland (Division IIIa, Sub-areas IV and VI) should be continued while not permitting an increase in fishing effort. An analytical assessment of the status of the stock is not yet possible, due to incomplete understanding of the dynamics of the stock, and a lack of sufficient and reliable data. While more and better data are being collected, this report describes the current fishery, in terms of metiers, catch and by-catch, time trends in effort and landings; this report analyses the trend in abundance observed in the stock; and this report advises on a TAC consistent with no increase in fishing effort and moderately accommodating for the trend in commercial catch rates.

Total catches of anglerfish in the North Sea and West of Scotland rose to a peak of 34,000 t in 1996, but subsequently declined to just over 12,000 t in recent years. This catch is taken predominantly by otter trawlers (75%), with a smaller share of gill netting (11%) mainly focused in area VIb. The remainder of the catch is taken in a wide range of gears. An international data compilation of catch data indicates that in all gears, except for the gill netting, the catch of anglerfish makes up a minor share of the total catch of mixed fisheries; other species in the same fisheries include sole, plaice, megrim, saithe, haddock, cod and Nephrops .

In recent years, rising trends in catch rates have been reported, possibly resulting in a tighter restriction on landings due to the TAC. While this recent rising trend is not debated by current analyses, there is insufficient ground to specify an exact figure for an update of catch limits. It is therefore recommended to implement an adaptive management scheme. The current TAC (2006) should be raised by an initial modest 10%. This rise in TAC should be conditional on a re-evaluation of the upward trend in the abundance of the stock in one year from now (spring 2007). When a comprehensive assessment of the stock becomes available, this should of course override the current advice.

STECF observations.

The SGRST has produced a comprehensive evaluation of the information available to it at the time of the meeting and has made a laudable attempt at answering its terms of reference.

STECF notes that the main sub-group conclusions and recommendations were as follows:

- While the observed rising trends in catch rates are not debated by current analyses, there are insufficient grounds to specify an exact figure for an update of catch limits.

- An adaptive management plan should be implemented

- The 2006 TAC should be raised by an initial modest 10%.

- The rise in TAC should be conditional on a re-evaluation of the upward trend in the abundance of the stock in one year from now (spring 2007).

- When a comprehensive assessment of the stock becomes available, this should of course override the current advice.

STECF notes that the sub-group’s recommendations are primarily based on the results of an analysis of catch rates over recent years. STECF also notes that while the observed increases in catch rates may be a reflection of increased recruitment to the fishery and/or increased survival of pre-recruits and juvenile recruits, they may also reflect changes in the fleet composition, fleet efficiency and/or fishing pattern. STECF is also aware that the changing quota possibilities for other species that are caught together with anglerfish may also have an influence on the observed catch rates of anglerfish. Nevertheless, the results of the analysis of both the Danish and UK commercial catch rates indicate similar trends, which may reflect an increase in the fishable stock.

STECF Conclusions and Recommendations

Based on the information presented in the SGRST 06-03 Working Group Report, STECF draws the following conclusions and recommendations:

The stock status of anglerfish in ICES Sub-areas IV and VI and its rate of exploitation are unknown. STECF is therefore unable to advise on a TAC for anglerfish in ICES areas IV and VI that is consistent with no increase in fishing mortality or fishing effort on this stock. Furthermore, in the absence of any reliable indicator of stock status of anglerfish in ICES areas IV and VI, STECF is unable to evaluate whether the agreed TAC of 15,000 t for 2006 will result in any change in fishing mortality on this stock.

STECF also notes that because anglerfish in ICES Sub-areas IV and VI are primarily caught in mixed demersal fisheries, management by TAC alone is unlikely to control the exploitation rate on the stock and recommends that that any agreed catch restrictions should be accompanied by complementary effort controls.

In the absence of any objective criteria on which to advise on appropriate catch or effort levels, STECF recommends managers adopt an adaptive and precautionary approach to managing the fisheries exploiting anglerfish in ICES Sub-areas IV and VI. Furthermore, because of the mixed species nature of the fisheries exploiting anglerfish, STECF recommends that the management measure most likely to result in a control on the exploitation rate is effort control.

STECF notes that at present, the only acceptable quantitative information likely to be indicative of relative trends in the fishable stock are commercial catch rates. STECF therefore suggests that in the short-term, management measures are adapted in response to relative changes in catch rates. STECF also notes that catch rates from some commercial fisheries have recently been increasing, which may reflect an increase in the fishable stock. However, the observed increases in catch rates are not necessarily an indication that recent exploitation rates are sustainable in the longer term, since the observed increases in catch rates may be primarily due to increased recruitment of anglerfish to the fishery, the causes of which remain unknown.

Hence, STECF suggests that until a reliable assessment of the state of the stock and its exploitation rate is available, managers should adopt a precautionary approach and implement measures with the aim of ensuring that fishing mortality on anglerfish does not increase. STECF therefore recommends that fishing effort for those fleets that exploit anglerfish (otter trawlers and gill netters) should not be allowed to increase. Furthermore, since there is no scientific basis to advise a TAC for anglerfish, that would correspond to no increase in fishing effort, and recognizing that setting a restrictive TAC that is out of line with the permitted effort for fleets exploiting anglerfish is unlikely to restrict fishing mortality on the stock, STECF recommends that catches and catch rates continue to be closely monitored throughout 2006 to determine whether the agreed TAC for anglerfish for 2006 is in line with the permitted effort. Any observed overall change in catch rate during 2006 could then provide the basis for adaptive management measures for 2007.

STECF recommends that when a comprehensive and acceptable assessment of the stock status of anglerfish in ICES Sub-areas IV and VI becomes available, the management measures for fleets exploiting this stock be re-assessed.

ANNEX I.

[pic] | COMMISSION OF THE EUROPEAN COMMUNITIES |

COMMISSION STAFF WORKING PAPER

REPORT OF THE THIRD MEETING OF THE

SUBGROUP ON REVIEW OF STOCKS. (SGRST-06-03)

OF THE

SCIENTIFIC, TECHNICAL AND ECONOMIC COMMITTEE FOR FISHERIES (STECF)

ANGLERFISH

Brussels, 24-27 April 2006

This report will be reviewed and evaluated by the Scientific, Technical and Economic Committee for Fisheries (STECF) by written procedure

This report does necessarily reflect the view of the STECF and the European Commission and in no way anticipates the Commission’s future policy in this area.

Summary Report of the STECF-SGRST-06-03 anglerfish meeting, 24-27 April 2006, Brussels. The fishery for anglerfish (Lophius piscatorius) in the North Sea and West of Scotland (Division IIIa, Sub-areas IV and VI) should be continued while not permitting an increase in fishing effort. An analytical assessment of the status of the stock is not yet possible, due to incomplete understanding of the dynamics of the stock, and a lack of sufficient and reliable data. While more and better data are being collected, this report describes the current fishery, in terms of metiers, catch and by-catch, time trends in effort and landings; this report analyses the trend in abundance observed in the stock; and this report advises on a TAC consistent with no increase in fishing effort and moderately accommodating for the trend in commercial catch rates. Total catches of anglerfish in the North Sea and West of Scotland rose to a peak of 34,000 t in 1996, but subsequently declined to just over 12,000 t in recent years. This catch is taken predominantly by otter trawlers (75%), with a smaller share of gill netting (11%) mainly focused in area VIb. The remainder of the catch is taken in a wide range of gears. An international data compilation of catch data indicates that in all gears, except for the gill netting, the catch of anglerfish makes up a minor share of the total catch of mixed fisheries; other species in the same fisheries include sole, plaice, megrim, saithe, haddock, cod and Nephrops. In recent years, rising trends in catch rates have been reported, possibly resulting in a tighter restriction on landings due to the TAC. While this recent rising trend is not debated by current analyses, there is insufficient ground to specify an exact figure for an update of catch limits. It is therefore recommended to implement an adaptive management scheme. The current TAC (2006) should be raised by an initial modest 10%. This rise in TAC should be conditional on a re-evaluation of the upward trend in the abundance of the stock in one year from now (spring 2007). When a comprehensive assessment of the stock becomes available, this should of course override the current advice. |

1. Introduction.

2. Background and Terms of Reference.

There are major uncertainties about catch and effort data for anglerfish ( Lophius piscatorius ), as well as limited knowledge about population dynamics and distribution. In addition, existing surveys have not proven useful in describing the population. In this situation, a two-stage approach has been advised. The first stage would be to substantially improve the quality and quantity of data collected on the fishery while maintaining exploitation at its current level, followed by a second stage of better informed advice and management. Following this two-step approach, the fishing mortality experienced by anglerfish in the North Sea and West of Scotland should not increase until conclusive evidence is presented on an acceptable exploitation level. STECF has recommended that anglerfish fisheries in divisions IV and VI should be continued while not permitting an increase in fishing effort. STECF has not yet been able to recommend operational methods for implementing such a limitation. While such a system is being developed, there is a requirement for an in-year adaptation of the TAC in line with a status-quo fishing mortality. In 2005, the UK has undertaken to provide revised data concerning catch rates from the commercial fishery.

The Terms of Reference for this meeting read:

1. Identify criteria for the management of anglerfish fisheries using effort management as the primary conservation instrument. The sub-group is requested to:

a. Identify, in terms of characteristics of fishing vessels, the gears they use and the areas and seasons in which they operate, the main fishing métiers that catch anglerfish in the North Sea and West of Scotland.

b. For each sector identified in (a), quantify the catches of anglerfish and of other species caught in the same fishing operations.

c. For each the sector identified in (a), provide details of historic effort deployed in each fishery, disaggregated by gear type and by Member State, for the longest available time-series.

2. Advise on a TAC for anglerfish in ICES areas IV and VI that is consistent with (a) no increase in fishing mortality or fishing effort on this species, (b) available information on commercial catch rates.

3. No stock assessment.

The biology, stock identity and distribution of the anglerfish on the Northern Shelf are not well understood. Basic information required for regular stock assessment, such as the spatial entity of the stocks, growth and maturation patterns, and the potential effect of spawning migration, presumably to deeper waters to the West of Scotland, are quite uncertain. Consequently, no regular stock assessment is available. ICES has attempted a length-based assessment in 2005, but in the absence of a better understanding of the processes involved, results can only be used with extreme caution. Mature females are extremely rare in market samples, resulting in a low estimated female spawning stock biomass, and a high (fishing) mortality. However, the catch composition can equally well indicate an emigration of the maturing females, and a much lower fishing mortality.

These uncertainties remaining in place, opportunities for an improved assessment are currently absent. Consequently, the catch projections in this report will be based on observed trends in catch rates.

4. Overview of this report.

Following this introduction, chapter 2 of this report presents available information on catch and effort in anglerfish fisheries in the Northern Shelf area, describing the metiers, the species composition of the catch, and time trends in catch and effort data.

Chapter 3 analysis time trends in stock abundance, as observed in historical diaries, observer programmes and logbook information.

Catch predictions are developed in chapter 4. These include detailed predictions for well documented sectors as well as a general prediction.

Finally, chapter 5 presents the main recommendations from this meeting.

5. Catch and effort

6. Data sources

Within its current work the SGRST on management of fishing effort of STECF has compiled data bases on fleet specific catch data for 2003-2004 and effort data 2000-2004. There is ongoing process to update the data base for 2005 in advance of the Sub-group’s meeting 5-9 June 2006 (SGRST 06-04). Such data bases are derived from the officially reported national logbook data bases hold by the member states. The aggregation processes applied to the data ensures that they are anonymous.

The defined fleet segmentation of the international landings, discard, age composition and effort data is by country, year, quarter, area, gear and mesh size groups which will allow the aggregation on an international level according to the fleets defined in Annex IIa of the Council Regulation No. 51/2006 subject to effort management. The provisional catch and effort data bases compiled during the first meeting of SGRST on management of fishing effort during 13-17 March 2006 (SGRST 06-01) do not consider the requested aggregation according to the special fishing conditions of Article 8.1, which allow additional days at sea for certain fleets. However, the fleet specific data bases on international catches and effort were provided to the SGRST meeting on anglerfish and analysed. The international fleet aggregation as consistently used among the member states’ fleets is described in Annex 3 to this report.

In this report, these provisional catch and effort data bases have been used for several purposes. During the meeting, however, some concern arose that part of the data may still be incomplete, or not yet validated. However, the current group felt it was not in a position to improve the data bases consistently, and therefore used the data as they were.

The international catch data base does not include information of discards of anglerfish. The landings weights are given in t for the years 2003 and 2004. Anglerfish landings from France and Ireland are not included. The data from the Netherlands were provided to the present meeting on anglerfish and included into the tables and graphs as taken by the beam trawls ≥80 mm.

The data base on effort contains fleet specific nominal efforts given in kW*days at sea for the years 2000-2004. SGRST considers such effort values critical regarding static gears.

7. Catches by area, gear type and mesh size, year and quarter

8. International overview

A breakdown of catches by area, gear type and mesh size, year and quarter is presented in Table 2.2.1 and Figures 2.2.1 – 2.2.3.

The major share of anglerfish landings is derived from otter trawl fishing (67-99%). Gill netting is second in rank. Beam trawling adds a minor quantity, predominantly in the 3rd and 4th quarter.

However, in area VIb, the landings are dominated by gill net catches (50-95%), with some otter trawl catches predominantly in the 3rd quarter. Overall, otter trawls make up for 75% of the catch, gill nets for 11%, and beam trawls for less than 5%.

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Figure 2.2.1 Officially reported landings of anglerfish in the North Sea, main gear type and quarter in 2003 and 2004. Data from the provisional and not yet validated STECF data base.

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Figure 2.2.2 Officially reported landings of anglerfish in the area West of Scotland, main gear type and quarter in 2003 and 2004. Data from the provisional and not yet validated STECF data base.

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Figure 2.2.3 Officially reported landings of anglerfish in the Rockall area, main gear type and quarter in 2003 and 2004. Data from the provisional and not yet validated STECF data base.

Table 2.2.1 Officially reported landings (t) of anglerfish by area, main gear type and quarter in 2003 and 2004.

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9. Danish catch and Effort

The geographical distribution of the Danish anglerfish landings are shown in Figs. 2.2.4 for 2004 and 2005. In the North Sea, landings are taken mainly in the part constituting the Norwegian Deeps, which is situated in the Norwegian EEZ of the North Sea. The other main fishing areas for anglerfish are the northern part of Fladen Ground (also in IVa) and in the Skagerrak (IIIa).

The majority of the Danish vessels taking anglerfish with demersal trawls are trawlers, which can be distributed according to length group as shown in Figure 2.2.5.

Tables 2.2.2 shows the distribution of Danish landings according to fishery defined by gear type and mesh size as currently used by Danish Fisheries Directorate for the North Sea, see text table below.

Fishery/gear | Mesh size, mm |

Dem. Trawl | >= 100 mm |

Nephrops trawl | 70 - 99 mm |

Shrimp trawl | 33 - 69 mm |

Industrial trawl | < = 32 mm |

Beam trawl | >= 80 mm |

This classification of the Danish fisheries is not as detailed as the one currently recommended by SGRST on management of fishing effort 13-17 March 2006 (SGRST 06-01). However, in relation to management of the fisheries for anglerfish it is sufficient at present, as the main Danish catches of anglerfish is taken by fisheries in the Norwegian zone of IV a applying demersal trawls with mesh size >= 120 mm. In recent years the fishery with demersal trawl in the Norwegian Deeps (in the Norwegian zone) has accounted for around 70 % of total Danish landings by all gears from the entire North Sea. In the Skagerrak (IIIa) the main fishery taking anglerfish is the Nephrops fishery, but the demersal trawl fishery also takes a significant part of the landings here. In IIIa the shrimp fishery comes in as no 3.

‘

In conclusion: The main Danish fishery taking anglerfish is carried out in the Norwegian Deeps, situated in the Norwegian EEZ, in ICES div. IVa by demersal trawl (mesh size >= 120 mm). second in overall importance is the fishery with Nephrops trawl conducted both in the North sea and IIIa, see Tables 2.2.2.

Figure 2.2.4. Distribution of Danish landings (tons) by ICES square in 2004 and 2005

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Figure 2.2.5. Danish vessel categories (by size) catching anglerfish.

Table 2.2.2a. Distribution of total Danish anglerfish landings by fishery. North Sea

Year | North Sea | tons | North Sea |

Other gear | beam trawl | dem_trawl | Nephr_trawl | ind_trawl | shrimp_trawl | total |

1992 | 124 | 80 | 811 | 348 | 260 | 63 | 1686 |

1993 | 88 | 45 | 621 | 94 | 347 | 98 | 1293 |

1994 | 87 | 59 | 822 | 283 | 195 | 64 | 1509 |

1995 | 72 | 57 | 345 | 254 | 127 | 172 | 1027 |

1996 | 48 | 17 | 756 | 280 | 129 | 234 | 1464 |

1997 | 47 | 64 | 1132 | 56 | 103 | 88 | 1489 |

1998 | 76 | 153 | 996 | 40 | 91 | 100 | 1456 |

1999 | 75 | 116 | 1106 | 39 | 84 | 76 | 1496 |

2000 | 52 | 88 | 1066 | 16 | 68 | 56 | 1347 |

2001 | 52 | 18 | 1343 | 7 | 67 | 53 | 1540 |

2002 | 41 | 59 | 1269 | 86 | 53 | 55 | 1563 |

2003 | 28 | 40 | 1508 | 59 | 30 | 42 | 1707 |

2004 | 57 | 45 | 1525 | 91 | 42 | 50 | 1809 |

2005 | 14 | 48 | 1412 | 96 | 26 | 17 | 1612 |

Table 2.2.2b. Distribution of total Danish anglerfish landings by fishery. Skagerrak (IIIa)

Year | IIIA | tons | IIIA |

Other gear | beam trawl | dem_trawl | Nephr_trawl | ind_trawl | shrimp_trawl | total |

1992 | 163 | 22 | 262 | 141 | 32 | 38 | 658 |

1993 | 83 | 12 | 263 | 163 | 9 | 35 | 565 |

1994 | 62 | 52 | 206 | 111 | 5 | 23 | 459 |

1995 | 48 | 82 | 97 | 62 | 1 | 21 | 312 |

1996 | 40 | 70 | 125 | 90 | 2 | 41 | 367 |

1997 | 58 | 137 | 183 | 139 | 8 | 25 | 550 |

1998 | 58 | 86 | 167 | 89 | 2 | 13 | 415 |

1999 | 82 | 41 | 121 | 105 | 1 | 12 | 362 |

2000 | 61 | 47 | 116 | 140 | 0 | 13 | 377 |

2001 | 44 | 18 | 86 | 211 | 4 | 11 | 375 |

2002 | 35 | 41 | 116 | 162 | 1 | 15 | 371 |

2003 | 27 | 4 | 27 | 147 | 1 | 10 | 217 |

2004 | 31 | 13 | 40 | 189 | 0 | 37 | 311 |

2005 | 18 | 5 | 83 | 135 | 0 | 30 | 272 |

10. Scottish catch and effort

Fishery descriptions based on standard ICES divisions are not very representative of the anglerfish fisheries landing into Scotland. Various sources of information including research vessel surveys, observer trips on board commercial boats, consultation with skippers and analysis of individual fishing trip records have been used to develop a description which is spatially more relevant to the biology of the species and activity of vessels. This approach has the advantage of being more aligned with the overall ‘Northern Shelf anglerfish’ stock definition used by ICES – which of course cuts across conventional ICES Areas.

FRS Marine Laboratory began a series of specific anglerfish surveys in 2005. Figure 2.2.6 shows the survey abundances derived from the coordinated activities of three charter vessels and RV Scotia – all using the same fishing gears and protocol in a predefined survey design. Using the distribution of survey abundances presented by statistical rectangle, those rectangles with abundance above the median (Figure 2.2.7) were defined as areas important for anglerfish. A similar approach was applied to the data collected during observer trips on board commercial vessels (described in more detail below) between 1999 and 2006 - there is a high degree of similarity. Figure 2.2.8 shows the combined area of high abundance from the survey and observer work. The area of highest anglerfish abundance is located along the shelf edge extending from an area to the north of Shetland down to the west of Islay in the south with the Rockall area also included. It is important to note that significant elements of stock distribution probably occur further south in areas fished by Ireland and France but not covered in the Scottish survey.

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Figure 2.2.6 Distribution of sample stations and survey abundance in the Scottish anglerfish survey (joint FRS/ industry). Catch rates expressed as kg/km2. The yellow, irregular polygons signify the four strata used in the survey including Rockall, south west Scotland, north west Scotland and North Sea

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Figure 2.2.7 Histogram showing distribution of abundances (relatively large number of low abundance stations) from the survey. The vertical line provides an arbitrary median cut-off point and the sampled rectangles corresponding to abundances above this median are shown in the panel on the right

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Figure 2.2.8 Overall distribution of statistical rectangles identified in FRS survey and from observer programme taken to represent the main ‘anglerfish fishery area’.

Anglerfish also occur in shallower and more inshore areas and around Scotland and these areas frequently coincide with Nephrops grounds which are well defined by soft substrate and are described the in ICES WGs. Figure 2.2.9 shows the distributions of the Nephrops areas in relation to the anglerfish area described above. The areas are mostly separate but where overlaps occur (usually statistical rectangles on the outer margins of Nephrops areas, shown in red) these are taken to be part of the anglerfish area.

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Figure 2.2.9 Statistical rectangle definition of the ‘anglerfish fishery area’ (orange), ‘Nephrops fishery area’ (buff) and ‘other’ (all other rectangles). Red rectangles indicate overlap between the anglerfish area and Nephrops area – these rectangles were subsequently included as part of the anglerfish area

Anglerfish are also found widely in squares outside the two areas defined and these form a third component of the overall distribution. All remaining statistical rectangles in areas IV ad VI were assigned to this fishery area. To the north and west, these squares sometimes contain moderate densities while further south in the North Sea the abundance declines.

These three areas, ‘main anglerfish area’, ‘Nephrops area’ and ‘other’ have been used to provide a spatial framework for a description of the fishery.

Within these areas, an analysis was then performed of the major gears and mesh sizes in use in order to identify key components of the fleet taking significant quantities of anglerfish. This work drew on the individual official logbook data held in the Scottish Executive fishery database FIN. Uncertainties in the completeness of information from this source limits the utility of this material but it is considered suitable for providing a broad based fishery description.

Table 2.2.3 shows fishing gears used by UK vessels landing anglerfish in Scotland from the three fishery areas. Data are shown for 2004 only but the picture is broadly similar for earlier years. Landings attributed to individual gear descriptions need to be treated cautiously since specific codes are sometimes entered incorrectly by fishermen. The gears are also grouped according to the broad EU gear categories and the pattern of overall landings for these gives a more reliable picture .The predominant gears involved in taking anglerfish are bottom trawls (71% of reported landings) and twin trawls (13.5%) with gill nets, pair trawls and Scottish Seine also contributing significant quantities. The analysis also shows that most of the landings come from the main anglerfish area (55%) with just over 22% coming from each of the other two areas.

Table 2.2.3 Fishing Gears used by UK vessels landing anglerfish in Scotland from the three fishery areas. Data shown for 2004 only. Landings listed by FIN gear code with description of the gear. Colour shading indicates the equivalent broad gear groups developed for categorising EU fleets.

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An analysis of the mesh sizes in use provides a more informative breakdown and illustrates which are the key contributors to anglerfish landings. Table 2.2.4 concentrates on the bottom trawl and twin trawl categories (84.5% of landings). Within the main anglerfish fishery area there is a pattern of increasing landings contribution with increasing mesh size. Trawls using >100mm in the bottom trawl and twin categories account for 83.4% and 16.5% respectively of the total landings of these gears combined. The >120mm bottom trawl category makes the single biggest contribution of any gear. Within the Nephrops area, the landings of anglerfish are predominantly made by the smaller mesh gears (<100mm), in particular the 80 – 99mm category in both bottom trawl and twin trawl groups. Catches in the ‘other’ area are predominantly made by the >120mm mesh gear and particularly by the bottom trawl category.

Table 2.2.4 Landings of anglerfish by UK vessels into Scotland for the two main gear categories (bottom trawls above and twin trawls below). Data within each of the three fishery areas are shown by mesh size with summaries for <100mm and >100mm.

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An indication of the number of vessels operating in the main groups of gears contributing anglerfish landings is given in Table 2.2.5. In the >100mm bottom trawl operating in the anglerfish area there has been a marked reduction in vessel numbers largely through decommissioning programmes operated in the UK. A similar picture can be seen for the <100mm twin trawl category operating in this area. A less marked decline is evident in the <100mm fishery operating in the Nephrops area. Table 2.2.6 provides an indication of the numbers of >100mm boats spending different amounts of time in the main anglerfish fishery area. Out of the 94 vessels operating in 2004 , 10 of them spent 90-100 % of their time there, while 25 (just over a quarter) spent more than 50 % of their time there. Anglerfish landings from the main anglerfish area appear to be made by groups of boats operating a range of behaviours. Some are resident most of the time, others move in and out of the area more often. The extent to which any of these groups is more dependent on anglerfish is difficult to judge and insufficient time was available to examine this in more detail. Clarke (2004) used cluster analysis to analyse the Scottish fleet operating in area IV and identified a very clean anglerfish component operating to the North West of the area but it is not clear how significant the contribution to overall anglerfish landings was by this cluster.

Table 2.2.5 Changes in the numbers of vessels operating in each of the main metiers contributing to anglerfish landings

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Table 2.2.6 Numbers of vessels in the bottom trawl >100mm grouping operating in the anglerfish main area for various percentages of their fishing time. For example in 2004, 10 vessels spent 90-100% of their time in the area, 25 vessels spent less than 10% of their time there.

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11. UK (EW&NI) catch and effort

Landings of anglerfish by UK vessels landing into England, Wales and Northern Ireland (EW&NI), and by EW&NI vessels landing abroad, are given in Table 2.2.7 by ICES subdivision, all gears combined. Landings have declined from more than 3000 tonnes in 1997 to less than 300 tonnes in 2005. Figure 2.2.10 shows the relative contribution of anglerfish landings in each ICES division to the total anglerfish landings. ICES Division VIb has contributed substantially more in recent years, in relative terms, to the total landings. Table 2.2.8 shows a further breakdown into two gear groupings, namely all gears excluding nets, and gillnets. These were the only gear groupings available to the meeting. Table 2.2.9 gives the proportion of anglerfish landings (expressed as a percentage) taken by nets, highlighting the importance of nets in Divisions IVa and VIb.

The effort associated with landings that included anglerfish is shown in Figure 2.2.11 for all gears excluding nets, and in Figure 2.2.12 for nets. The effort is measured as number of days fished. A strong decline in effort since the mid- to late-1990’s is indicated for both gear groups, but these trends should be interpreted with care because landings that did not include anglerfish (for reasons of availability, discarding or mis-reporting) are not incorporated.

Figure 2.2.13 describes the total number of landings that included anglerfish, categories by vessel length. The greatest number of anglerfish landings was made by vessels of 10-20m in length.

Table 2.2.7 . Landings of anglerfish by UK vessels landing into EW&NI, and by EW&NI vessels landing abroad, by ICES subdivision, all gears combined.

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Figure 2.2.10 . Relative contribution of anglerfish landings in each ICES division to total anglerfish landings.

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Table 2.2.8 . Landings of anglerfish by UK vessels landing into EW&NI, and by EW&NI vessels landing abroad, by ICES division, for the all gears excluding nets, and for nets.

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Table 2.2.9 . Proportion of anglerfish landings (expressed as a percentage) taken by nets. Data are for UK vessels landing into EW&NI, and by EW&NI vessels landing abroad, by ICES division.

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Figure 2.2.11 . Effort (number of days fished) associated with landings that included anglerfish, for all gears, excluding nets, given by ICES division.

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Figure 2.2.12 . Effort (number of days fished) associated with landings that included anglerfish, for nets, given by ICES division.

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Figure 2.2.13 . Number of landings that included anglerfish, categorised by vessel length in ICES Divisions IV and VI in 2005. A vessel in the [10,15) length category is 10m or larger, but less than 15m. Date are for UK vessels landing into EW&NI, and EW&NI vessels landing abroad.

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12. Species composition in catches of trips catching anglerfish

13. International data

The species composition of the catches of the main gears catching anglerfish were analysed from the provisional (and incomplete) international data base on catches and efforts, as compiled during the first meeting of SGRST on management of fishing effort during 13-17 March 2006 (SGRST 06-01). As indicated above, some concern exists on the content of these data bases.

Results are presented in Figures 2.3.1 to 2.3.3 below. In the areas IV (North Sea) and Via (West of Scotland), the catch of anglerfish makes up a minor share of the total catch of mixed fisheries, predominantly taken by otter trawls; other species in the same fisheries include sole, plaice, megrim, saithe, haddock, cod and Nephrops. In area VIb, however, most anglerfish is taken in gill nets, and by-catches of other species make up a much smaller part. The additional catch of anglerfish in otter trawls in this area, however, do come with a by-catch of haddock, Nephrops and others.

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Figure 2.3.1 Landings composition (t) of anglerfish (ANF), cod (COD), haddock (HAD), Nephrops (NEP), plaice (PLE), saithe (POK), sole (SOL) and whiting (WHG) in the North Sea by gear in 2003 and 2004. The grey bars in the background present the contribution of anglerfish ten times enlarged.

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Figure 2.3.2 Landings composition (t) of anglerfish (ANF), cod (COD), haddock (HAD), Nephrops (NEP), plaice (PLE), saithe (POK), sole (SOL) and whiting (WHG) in the area West of Scotland in 2003 and 2004. The grey bars in the background present the contribution of anglerfish ten times enlarged.

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Figure 2.3.3 Landings composition (t) of anglerfish (ANF), cod (COD), haddock (HAD), Nephrops (NEP), plaice (PLE), saithe (POK), sole (SOL) and whiting (WHG) in the Rockall area by gear in 2003 and 2004.

Table 2.3.1 Landings composition (t) of anglerfish (ANF), cod (COD), haddock (HAD), Nephrops (NEP), plaice (PLE), saithe (POK), sole (SOL) and whiting (WHG) by area and gear in 2003 and 2004.

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14. Species composition in catches of Danish fisheries catching anglerfish

Information on the species composition of the landings from Danish fisheries taking anglerfish is available from the Danish logbook records. Table 2.3.2 shows the species composition in landings from the Norwegian Deeps by the common gear used in this fishery (trawls with mesh size >= 120 mm) for 2004 and 2005. The relative species composition appears to be rather similar for these two recent years. Anglerfish constitutes around 13% by weight of the landings, while the most important species by weight is saithe.

In addition to the logbook information, more detailed information of the composition of the catch, including the discard component is available for 2005 from the Danish at-sea-samples conducted in the 1st and 2nd quarter of 2005 in fishing trips for anglerfish and other demersal species (mesh size = 122 mm). In these samples anglerfish constituted around 25% of the landed component of total catch. This is a much higher fraction than recorded by logbooks. However, the logbook records also include many trips directed more at other species including Nephrops and therefore the overall percentage here is smaller. It is however noted that the overall patterns in species composition are similar, see Figs.2.3.4. Cod, saithe and Nephrops and to a lesser extent haddock, ling and witch flounder seem to be the other important components of the landings. The logbook data on landings composition are also available. The at-sea-samples also provide data on corresponding discards as shown in Figure 2.3.5 and 2.3.6. Note here the dominating ‘other species’ component. Cod also appears to be a significant component of the discards. One must be cautious to extrapolate to total discards corresponding to total landings from these few samples.

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Figure 2.3.4 Species composition in Danish landings with anglerfish. Data from logbooks.

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Figure 2.3.5 Species composition in Danish landings with anglerfish. Data from observer programmes.

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Figure 2.3.6 Species composition of discards in fisheries for anglerfish. Data from observer programmes.

Table 2.3.2 Species composition (see also Figures 2.3.5 and 2.3.6)

2004 | 2005 |

Speies | tons landed | % of total | tons landed | % of total |

Tusk | 98 | 1.1 | 80 | 0.8 |

Nephrops | 730 | 8.2 | 910 | 9.7 |

Anglerfish | 1200 | 13.4 | 1254 | 13.3 |

Hake | 127 | 1.4 | 215 | 2.3 |

Haddock | 616 | 6.9 | 545 | 5.8 |

Ling | 447 | 5.0 | 543 | 5.8 |

Saithe | 3442 | 38.5 | 2920 | 31.0 |

Plaice | 480 | 5.4 | 556 | 5.9 |

Lemon sole | 161 | 1.8 | 217 | 2.3 |

Witch | 333 | 3.7 | 424 | 4.5 |

Cod | 794 | 8.9 | 1081 | 11.5 |

Others | 505 | 5.7 | 676 | 7.2 |

Grand Total | 8933 | 100.0 | 9421 | 100.0 |

15. Species composition in catches of Scottish fisheries catching anglerfish

An analysis of catches of other species taken with anglerfish was performed for the main metiers contributing to anglerfish landings. Results for 2003 and 2004 are shown in Figure 2.3.7. The species included were anglerfish, megrim, ling, cod, haddock, whiting, saithe and Nephrops - note this does not represent all species caught and results are presented only in absolute terms, not as percentage compositions. Landings of other species were, however, relatively small. Information is provided for the main metiers described above and the overall importance of each metier in terms of total landings can be seen together with the relative importance of the associated species in each.

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Figure 2.3.7 Landings (kg) of species caught in association with anglerfish in each of three main fishery areas and by principle metiers in 2003 (upper panel) and 2004 (lower panel). Results shown as a stacked histogram of UK landings into Scotland

The anglerfish area has the highest overall landings caught in association with anglerfish with the >100mm bottom trawls making the largest contribution. This metier has a mixed catch composition with haddock the most important species and cod and anglerfish the next most important. In the Nephrops area the largest overall landings associated with anglerfish come from the <100mm gears but here the predominant species is Nephrops, with anglerfish the third most important after haddock. Overall landings associated anglerfish in the ‘other’ area are greatest in >100mm bottom trawl category where haddock again predominates – anglerfish make a relatively small contribution in this category. Rather similar results are obtained for 2003 and 2004 with slight reductions in the amounts of cod in the large mesh metiers.

Anglerfish apparently contribute relatively low proportions to the landings in most of the metiers described. Care is, however, required here, since even within the main anglerfish metier, individual vessels show considerable variability in time spent in the anglerfish area (see above) and can be expected to show marked variation in catch composition. Discussion with individual skippers suggests that even within a single statistical rectangle, catch composition can vary a great deal particularly where the bathymetry changes rapidly. The cluster analysis performed on individual landing records from ICES area IV (Clarke, 2004) showed that a very clean anglerfish fishery could be identified. As discussed above, further analysis of the main, large mesh trawl metier operating in the anglerfish area is required to provide a more comprehensive picture of catch composition. This was beyond the scope of the present meeting.

16. Species composition in catches of UK (EW&NI) fisheries catching anglerfish

The species composition of landings by ICES sub-division and gear groupings (all gears excluding nets, and nets) is given in Figure 2.3.8. Anglerfish landings are a relatively minor component (<10%) of landings by all gears excluding nets, but accounts for a larger component of net landings, particularly in Division IV. The proportion of species taken by nets in each area is shown in Table 2.3.3.

Figure 2.3.8 . Species composition (by weight) of landings by sub-division and gear grouping for 2003-5. Data are for landings that included anglerfish by UK vessels landing into EW&NI, and EW&NI vessels landing abroad. Anglerfish has the species code “ANF” ; CRR indicates Red Crab.

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Table 2.3.3 . Proportion of landings (expressed as a percentage) taken by nets for each species and ICES sub-division in 2005. Data are for landings that included anglerfish by UK vessels landing into EW&NI, and EW&NI vessels landing abroad. A “-” indicates that species did not occur with anglerfish landings in the relevant area. Anglerfish has the species code “ANF”.

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17. Trends in catch and effort.

18. International data on landings

Total catches of anglerfish in the North Sea and West of Scotland rose to a peak of 34,000 t in 1996, but subsequently declined to just over 12,000 t in recent years. The majority of the landings is derived from area IVa. Most areas showed a maximum in landings in the mid-1990s, but landings from area IIIa peaked in the early 1990s, while the landings from area VIb showed a peak in 1999-2001.

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Figure 2.4.1 Trend in international landings of anglerfish per fishing area. Data for 2004 provisional.

Table 2.4.1 .a Nominal landings (t) by year, updated: area IIIa.

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Table 2.4.1 .b Nominal landings (t) by year, updated: area IV.

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Table 2.4.1 .c Nominal landings (t) by year, updated: area VI.

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19. International data on effort

Trends in effort of the main fisheries catching anglerfish were analysed from the provisional and not yet validated STECF data base. See figures 2.4.2 – 2.4.4 and Table 2.4.2. For several gears, a declining trend was observed, probably due to general fishing effort decommissioning schemes. In addition to this trend, effort by otter trawlers using 100-119 mm mesh sizes in areas IV and VIa declined, while that using mesh sizes <100 and >=120 increased; this indicates a shift away from the intermediate mesh sizes.

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Figure 2.4.2 Nominal effort (kW*days at sea) in the North Sea by gear, year and quarter, 2000-2004. Data from the provisional and not yet validated STECF data base.

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Figure 2.4.3 Nominal effort (kW*days at sea) in the area West of Scotland by gear, year and quarter, 2000-2004. Data from the provisional and not yet validated STECF data base.

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Figure 2.4.4 Nominal effort (kW*days at sea) in the Rockall area by gear, year and quarter, 2000-2004. Data from the provisional and not yet validated STECF data base.

Table 2.4.2 Nominal effort (kW*days at sea) by area, gear, year and quarter, 2000-2004.

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20. Trends in the landings and effort in the Danish fisheries

Figure 2.4.5 (and Tables 2.4.3 and 2.4.4) show the development of in landings and corresponding effort in the main Danish fisheries where anglerfish is caught. Note that from 2000 to 2004 landings from the North Sea increased by around 34 %. However, considering the Norwegian deeps alone the increase was 43%. During this period effort, as recorded in logbooks, also increased, but not in a corresponding magnitude.

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Figure 2.4.5 Development in Danish effort, 1996-2005 (logbook information)

Table 2.4.3. Danish landings (tons) of anglerfish distributed by gear/fishery.

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21. Figure 2.4.10 Stacked charts showing the trends in landings (kg) by towed gears with meshes >100mm (left panels) and <100mm (right panels) and operating in the three main fishery areas defined in Section 2.2 (top, middle and bottom panels).

Fuller details of landings and effort trends for the most important metiers, the bottom trawl and twin trawl gears of >100mm and <100mm, are shown in Tables 2.4.7 and 2.4.8 respectively. These data confirm the downward trend in both landings and effort in the larger mesh and also show the rise in landings in the small mesh gear fishery operating in the Nephrops area. Interestingly, the upward effort trend for this category is not so marked. This may indicate an increased abundance but LPUEs have not been calculated owing to uncertainty in the landings information.

Table 2.4.7 Trends in catch and effort in the large meshed (>100mm) bottom trawl metier (above) and twin trawl metier (below) operating in each of the three anglerfish fishery areas defined in section 2.2

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Table 2.4.8 Trends in catch and effort in the small meshed (<100mm) bottom trawl metier (above) and twin trawl metier (below) operating in each of the three anglerfish fishery areas defined in section 2.2

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22. Anglerfish TACs by country and geographic area

The Official Journal of the European Union, L 16, Volume 49, 20 January 2006 lists the TACs for anglerfish for 2005 and 2006. Figure 2.5.1 and Table 2.5.1 summarises this information.

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Figure 2.5.1 . Total Allowable Catch of anglerfish in 2005 and 2006 by country.

Table 2.5.1 . Total Allowable Catch of anglerfish in 2005 and 2006 by country and area.

Anglerfish Lophiidae | Zone: IIa (EC waters), IV (EC waters) ANF/2AC4-C |

Belgium | 365 |

Denmark | 804 |

Germany | 393 |

France | 75 |

The Netherlands | 276 |

Sweden | 9 |

UK | 8.392 |

EC | 10.314 |

TAC | 10.314 |

Anglerfish Lophiidae | Zone: IV (Norwegian waters) ANF/04-N |

Belgium | 53 |

Denmark | 1.343 |

Germany | 21 |

The Netherlands | 19 |

UK | 314 |

EC | 1.750 |

TAC | Not relevant |

Anglerfish Lophiidae | Zone: Vb (EC waters), VI, XII, XIV ANF/561214 |

Belgium | 168 |

Germany | 192 |

Spain | 180 |

France | 2.073 |

Ireland | 469 |

The Netherlands | 162 |

UK | 1.442 |

EC | 4.686 |

TAC | 4.686 |

23. Trends in the stock

24. Scottish historical diary data

During 2004, in order to get a more accurate and detailed picture of the Scottish anglerfish fishery, information was collated from the personal diaries of Scottish skippers operating across the Northern Shelf. Diaries were obtained from vessels with a range of different sizes, different engine power and gear configuration and different target species. An analysis of these data was presented in a working paper provided to the WGNSDS Review Group (Bailey et al. 2004). Some additional data were obtained in 2005 from 2 new vessels and complete 2004 data for 3 of the original vessels. The complete data set, consisting of seventeen diaries with useful information on location and catch rate were considered by WGNSDS at its 2005 meeting. The diaries covered a range of time periods from 2 to 10 years. Annual mean catch rates of anglerfish ranged from approximately 10 Kg/hr for a vessel likely to be targeting Nephrops to over 70 Kg/hr for vessels targeting demersal fish species.

To take vessel size effects into account, generalized additive models were fitted using R (http://CRAN.R-project.org/). Catch rate in Kg/hr was modelled with month, year and vessel. The smooth terms (month and year) are represented using penalized regression splines with smoothing parameters selected by cross validation. While there were differences in seasonal patterns between areas, all the analyses indicated increased catch rates in recent years. The year effect from the analysis is shown in Figure 3.1.1. A more complete description of the analysis and discussion of the results can be found in ICES (2006).

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Figure 3.1.1. Annual trend from the GAM analysis of all the Scottish diary data.

Following recommendations made by ICES that the diary data scheme should be continued and extended, FRS (in consultation with the fishing industry) have recently established a new monkfish tallybook project. The project is being operated in conjunction with fisher’s organizations who are responsible for distributing the tallybooks, co-ordinating the returns and allocating a vessel code before the data are forwarded to FRS. The tallybooks are filled in on a haul by haul basis to give weight caught by size category and information on haul location, duration and depth. So far, the time series is short, with the first returns from fishing trips at the end of December 2005 and the most recent from the first week of April 2006. Returns have so far been received from 36 vessels (over 3000 hauls in total) with a wide spatial coverage and different target species. Average catch rates cover a similar range to those calculated from the diary data (around 10 Kg/hr for boats targeting Nephrops to over 100 Kg/hr for whitefish boats.

Some of the vessels which provided diary data are now participating in the tallybook scheme and it has been possible with the help of the fisher’s organizations involved, to match up some of these vessels. Mean first quarter catch rates from these vessels are shown in Figure 3.1.2. It is difficult to conclude whether there has been any overall change in catch-rate in the most recent year: some vessels appear to have experienced an increase in catch rate in the 1st quarter of 2006 compared to the years prior to 2005, while others have experienced a decrease or no change.

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Figure 3.1.2. Mean first quarter catch rates from vessels provided both diary data and participating in the tallybook scheme.

25. Observer programmes

26. Scottish observer data.

FRS Marine Laboratory has conducted an on-board commercial vessel observer programme for over 30 years, these data are regularly fed into the ICES assessment Working Groups. Data on anglerfish observed catches are available since 1999 and were included in analysis of catch rates including data collected as recently as the first quarter 2006. As part of the enhanced programme of work on anglerfish, including survey work and the collection of tally book data from fishermen (see Section above), additional sampling was begun in 2005 by the Shetland Fishery College (under contract to FRS). This has continued and been further enhanced in 2006 and the total number of trips undertaken in the first quarter is shown in the text table below. FRS routinely carries out around 14 observer trips in the first quarter so the additional sampling represents a doubling of observer effort.

FRS Demersal Observer Trips | 14 |

FRS Nephrops Observer Trips | 2 |

Extra FRS Anglerfish Observer Trip s | 4 |

NAFC Anglerfish Observer Trips* | 6 |

SFF Observer Trips+ | 2 |

Total Trips 28 |

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Figure 3.2.1 Distribution and catch rates of anglerfish from observer trips conducted in Scotland between 1999 and 2006(Q1 only). The number of statistical rectangles with available data is also shown.

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Figure 3.2.2 Distribution of observed catch rates from the 2006 Scottish Observer programme quarter 1 for all gears showing in more detail the relationship between higher catch rates and the 200m depth contour

Figure 3.2.1 shows the distribution of all observer trips between 1999 and 2006 together with an indication of the catch rate. Results suggest an increase in catch rate in recent years, particularly along the continental shelf edge although the inter-year spatial variability in sampling and the changing sampling numbers confound the interpretation.

Figure 3.2.2 shows the distribution and catch rates observed in the first quarter of 2006. Despite some variability between samples taken in the same statistical square, there is nevertheless a pattern of higher catch rate close to the continental shelf and lower values in shallower water. This distributional pattern is further shown in Figure 3.2.3 which plots average catch rates by statistical square for the entire data series. It is possible to subdivide the data into the different gears operating in different parts of the overall anglerfish distribution. Figure 3.2.4 shows the results for light and heavy trawl while Figure 3.2.5 shows Nephrops trawl results. The former operate widely over the northern North Sea and offshore west of Scotland where catch rates were highest while he latter are restricted to areas of soft mud bottom and tend to have lower catch rates.

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Figure 3.2.3 Average catch rate per sampled statistical square for all data across all years. Scale indicates that highest catch rates to the west of Scotland were around 100kg /hour

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Figure 3.2.4 Average catch rate per sampled statistical square for light trawl and heavy trawl across all years.

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Figure 3.2.5 Average catch rate per sampled statistical square for Nephrops trawls across all years. Activity by these vessels is concentrated in soft sediment areas where catch rates are generally lower.

Figure 3.2.6 shows a series of catch rate trends for different groupings of the observer data. Combining all data gives the largest catch rate rise (top panel) but this includes only the first quarter 2006 data which distorts the picture. It is well known that catch rates of anglerfish vary seasonally with lower rates occurring in the second and third quarters. A more appropriate overall impression is gained in the second panel. These two plots, however, group all data and make no allowance for the different anglerfish population characteristics in different areas or the relative numbers sampled from year to year in different places. The third panel shows the catch rates observed in the main anglerfish fishery area. Increases in abundance in recent years are clearly apparent although with smaller sample numbers the data are noisier. The absolute catch rate is also at a higher level when this area is considered in isolation. The lowest panel indicates that in the Nephrops part of the anglerfish fishery, catch rates are much lower but that higher rates in the last couple of years can still be seen.

All gears all areas 1999- 2006 |

All gears all areas Q1 only 1999 – 2006 (takes account of variable catch rate throughout the year) |

All gears Q1 anglerfish fishery area rectangles 1999-2006 |

All gears Q1 in Nephrops rectangles 1999-2006 |

Figure 3.2.6 Trends in observed catch rate (Scottish Observer programme) between 1999 and 2006 for different subsets of the available data. The number of rectangles sampled is shown for each year and the number on the vertical axis indicates catch rate.

Results from a number of categories of vessel show increases in catch rate in recent times, sometimes quite dramatic increases are apparent. Table 3.2.1 shows average catch rates over the period 1999-2006 for each of three fishery areas described in Section 2.2. In each case increases are evident although the magnitude of the catch rate (reflecting the different types of anglerfish population and the different characteristics of vessels operating in the different areas) varies somewhat.

Table 3.2.1 Average catch rates in Q1 (kg/hr) from UK Scotland observer programme between 1999 and 2006. Average applied across all gears in each of the three fishery areas defined within areas IV and VI combined.

Rectangles in anglerfish fishery area

1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 |

9.64 | 26.67 | 9.16 | 25.27 | 15.14 | 26.86 | 42.08 | 42.35 |

Rectangles in Nephrops fishery area

1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 |

2.64 | 2.29 | 0.03 | 1.44 | 3.11 | 5.21 | 3.14 | 5.56 |

Other rectangles:

1999 | 2000 | 2002 | 2003 | 2004 | 2005 | 2006 |

2.28 | 2.22 | 2.76 | 3.69 | 0.80 | 5.49 | 5.85 |

Improving the basic data for anglerfish is an important requirement for improved assessments in the future. Increasing the available directly observed catch rates are seen as a crucial element of this. The use of these enhanced data at the end of a data series, does however, potentially create difficulties in interpretation of trends observed, particularly where the extra effort has been directed at the species of interest. This problem is investigated in the next section.

27. Statistical analysis of the Scottish observer data.

The Scottish observer programme relevant for the anglerfish fishery has run from 1999 onwards. Over the years, the spatial coverage of this programme has changed. In recent years, observed catch rates have generally gone up, but it is yet unclear whether this was restricted to the core distribution area, and to what extend the change in spatial coverage of the observer programme might have blurred our view. In this paragraph, the data will be analysed to disentangle the spatial and temporal components.

Available data: Mean landing per unit of effort LPUE, broken down by year*quarter*gear type*ICES rectangle. Note that the original data by haul were already aggregated by rectangle; the number of hauls was therefore used as a weighing variable. The number of hauls and the number of data records available are summarised in Table 3.2.2. Five gear types were distinguished: heavy trawl, seines, light trawl, Nephrops trawls and pair trawls.

Statistical model: Generalised Linear Model of the LPUE as a function of the year, quarter, gear type and rectangle. The spatial pattern is coded by a simple class variable (rectangle), without spatial autocorrelation. Potential density dependence in the distribution is analysed by a so-called «Mandel`s bundle of straight lines» model (Mandel 1959; Milliken and Johnson 1989). This is essentially a two-step fitting procedure. In the first step, a simple model is fitted:

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where year, quarter, gear and rectangle are class variables and [pic] is an error term with a Poisson distribution. The Poisson error distribution and logarithmic link function accommodate multiplicative effects, while allowing for zero observations. Posterior inspection of the residuals did not show major deviations from this assumed distribution. From this first simple model fit, parameter estimates for each rectangle are derived, which are subsequently added to the data set as an extra explanatory variable, using the parameter estimate corresponding to the rectangle of each record. Subsequently, a second model is fitted, including this extra variable in interaction with other variables of interest:

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where Mandel(rectangle) indicates the parameter estimate of the rectangle concerned in the first model. This procedure allows the estimation of general density dependent trends in the distribution, while using a very limited number of parameters.

The analysis of variance (Table 3.2.3) indicates that density dependent changes in the distribution pattern of catch rates, though statistically significant, play a minor role. About 1% of the total deviance is explained by «Mandel`s bundle of straight lines». Moreover, disproportionate concentration of the anglerfish LPUE in the rectangles of high average LPUE occurs in 2000 and 2005 (Table 3.2.4), where 2000 was one of the years with a low over-all abundance, and 2005 showed a high abundance (Figure 3.2.8). The absence of density dependent changes in the distribution makes it rather unlikely that the anglerfish shows density dependent migration, or that the observed temporal trend in the catch rates is merely the effect of the fishing effort shifting towards more profitable anglerfish areas.

The mean observed LPUE (Table 3.2.5) differs substantially from the mean predicted LPUE (Table 3.2.6 and 3.2.7). Most notable is that the pronounced rise in mean LPUE observed since 2003 (three-fold or more) is not completely reflected in the predicted LPUE. This indicates that during these years the sampling programme has unintentionally concentrated on the rectangles of high anglerfish catches. Following correction, a doubling in catch rates remains.

The lower bound to the 95% confidence intervals per year and quarter are listed in Table 3.2.8. On average, the lower bound of the 95% confidence interval for the years from 2004 onwards is more or less equal to the best estimate of the preceding years, that is: the rise is just or just not significant. It should be noted that the current analysis is based on data aggregated at the rectangle level. Re-analysis using the haul by haul data might yield a significant result.

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Figure 3.2.7 . Predicted spatial distribution of the landings per unit of effort in the Scottish observer programme, following correction for gear and temporal trends.

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Figure 3.2.8 . Trends in the average predicted landings per unit of effort (kg/hr) by year and quarter,s as derived from the statistical analysis of the Scottish observer programme.

Table 3.2.2 . The number of hauls/observations by year and quarter in the Scottish observer programme.

quarter |

Year | 1 | 2 | 3 | 4 | sum |

1999 | 203 / 022 | 290 / 021 | 250 / 022 | 196 / 023 | 939 / 088 |

2000 | 184 / 014 | 276 / 022 | 220 / 019 | 308 / 024 | 988 / 079 |

2001 | 162 / 015 | 431 / 034 | 368 / 029 | 396 / 036 | 1357 / 114 |

2002 | 232 / 023 | 321 / 024 | 281 / 024 | 177 / 022 | 1011 / 093 |

2003 | 247 / 017 | 246 / 019 | 173 / 018 | 143 / 018 | 809 / 072 |

2004 | 127 / 015 | 390 / 027 | 237 / 020 | 149 / 019 | 903 / 081 |

2005 | 183 / 022 | 280 / 025 | 200 / 019 | 336 / 039 | 999 / 105 |

2006 | 422 / 069 | (422 / 069) |

Table 3.2.3 Analysis of variance of the landings per unit of effort in the Scottish observer programme. The analysis is developed as a type-1 model: terms were added to the analysis in the order specified.

Source | Deviance | % | df | MS | F | p |

Year | 26,719 | 19 | 7 | 3817.06 | 81.899 | 0.000 |

Quarter | 3,719 | 3 | 3 | 1239.52 | 26.595 | 0.000 |

Gear | 46,194 | 32 | 4 | 11548.45 | 247.783 | 0.000 |

Rectangle | 40,800 | 28 | 121 | 337.19 | 7.235 | 0.000 |

Mandel(rectangle)*year | 879 | 1 | 7 | 125.58 | 2.694 | 0.009 |

Explained | 118,311 | 82 | 142 | 833.18 | 17.877 | 0.000 |

Unexplained | 26,007 | 18 | 558 | 46.61 |

Total | 144,318 | 100 | 700 | 206.17 |

Table 3.2.4 Parameter estimates of «Mandel`s bundle of straight lines». Positive parameter values indicate an increased LPUE in the rectangles with an above-average anglerfish density, that is: a more than proportionally accentuated spatial distribution in the year concerned.

Year | Mandel(rectangle) |

1999 | -0.2314 |

2000 | 0.0988 |

2001 | -0.0384 |

2002 | -0.1614 |

2003 | -0.3103 |

2004 | 0.0460 |

2005 | 0.3530 |

2006 | 0.2438 |

Table 3.2.5 Average observed landing per unit of effort (kg/hr), by year and quarter, averaged over all rectangles visited in the observer programme.

quarter |

Year | 1 | 2 | 3 | 4 | mean |

1999 | 4.78 | 6.69 | 4.21 | 8.18 | 5.98 |

2000 | 10.98 | 7.41 | 3.23 | 3.61 | 5.88 |

2001 | 5.51 | 3.53 | 2.87 | 4.33 | 3.87 |

2002 | 7.89 | 4.45 | 3.55 | 4.02 | 4.97 |

2003 | 6.82 | 6.22 | 3.54 | 9.3 | 6.46 |

2004 | 10.39 | 10.76 | 10.6 | 5.26 | 9.36 |

2005 | 15.96 | 6.69 | 7.66 | 21.94 | 14.47 |

2006 | 33.82 |

Table 3.2.6 Average predicted landing per unit of effort (kg/hr), by year and quarter, averaged over all rectangles in the data set. Predictions based on the simple, density-independent model .

quarter |

Year | 1 | 2 | 3 | 4 | mean |

1999 | 15.66 | 11.16 | 9.98 | 13.00 | 12.45 |

2000 | 19.05 | 12.22 | 11.04 | 14.56 | 14.20 |

2001 | 15.63 | 9.86 | 9.19 | 11.57 | 11.51 |

2002 | 19.87 | 13.86 | 12.29 | 16.13 | 15.52 |

2003 | 19.82 | 13.40 | 12.18 | 15.85 | 15.31 |

2004 | 39.24 | 24.64 | 22.70 | 30.60 | 29.24 |

2005 | 31.03 | 21.49 | 19.78 | 24.42 | 24.20 |

2006 | 28.24 |

Table 3.2.7 Average predicted landing per unit of effort (kg/hr), by year and quarter, averaged over all rectangles in the data set. Predictions based on «Mandel`s bundle of straight lines» model .

quarter |

Year | 1 | 2 | 3 | 4 | mean |

1999 | 15.89 | 11.07 | 9.77 | 12.45 | 12.30 |

2000 | 18.56 | 11.59 | 10.34 | 13.42 | 13.46 |

2001 | 15.18 | 9.33 | 8.62 | 10.61 | 10.88 |

2002 | 19.32 | 13.19 | 11.54 | 14.86 | 14.71 |

2003 | 20.30 | 13.42 | 11.98 | 15.32 | 15.25 |

2004 | 39.57 | 24.23 | 22.04 | 29.26 | 28.72 |

2005 | 33.66 | 22.85 | 20.76 | 24.99 | 25.57 |

2006 | 26.83 |

Table 3.2.8 Lower 95% confidence bounds of the predicted landing per unit of effort (kg/hr), by year and quarter, averaged over all rectangles in the data set. Predictions based on «Mandel`s bundle of straight lines» model.

quarter |

Year | 1 | 2 | 3 | 4 | mean |

1999 | 7.50 | 5.30 | 4.66 | 6.00 | 5.86 |

2000 | 9.42 | 5.85 | 5.18 | 6.81 | 6.80 |

2001 | 7.30 | 4.52 | 4.18 | 5.14 | 5.26 |

2002 | 9.43 | 6.42 | 5.62 | 7.21 | 7.16 |

2003 | 9.43 | 6.16 | 5.53 | 7.13 | 7.06 |

2004 | 19.72 | 12.02 | 10.98 | 14.75 | 14.34 |

2005 | 17.40 | 11.88 | 10.87 | 13.36 | 13.38 |

2006 | 15.28 |

28. UK (EW) observer data

A time series of CPUE trends for three gear groupings (demersal, Nephrops and beam trawls) were derived using the CEFAS observer database (Figure 3.2.9). CPUE is calculated as kg caught per observed tow hours. Time series are given for all quarters combined, and for quarter 1 only by ICES sub-division. The number of observed trips is low (indicated on each plot by n), so an overall trend for all sub-divisions combined is shown in each plot. Only quarter 1 data are available for 2006, so trends are also shown for quarter 1 for comparability, although the number of observed trips for demersal and beam trawls are then very low.

The demersal trawl CPUE series shows an increase in CPUE level in 2003-5 compared to 1999-2002. For Nephrops trawls, where anglerfish occurs as a bycatch, the CPUE series fluctuates substantially prior to 2003, with a lower, more stable period in 2003-2006. The beam trawl CPUE shows a general decline, but is based on very few observed trips.

[pic]

Figure 3.2.9 . Anglerfish CPUE trends (kg per observed tow hours) by ICES sub-division, based on UK (EW) observer data for three gear groupings: demersal (top), Nephrops (middle) and beam trawls (bottom). The first column combines all four quarters, while the second column refers to quarter 1 only. The number of observed trips (n) on which the solid curves (Divisions IV and VI combined) are based is given in the top right corner. The secondary axis in the top plots applies to the solid curves only.

29. Logbook data

30. International data

An overview of the data from the provisional and not yet validated STECF data base of logbook information is presented in Table 3.3.1 and Figures 3.3.1-3.3.3. The time period covered (2003 and 2004) is rather short to conclude on trends.

Table 3.3.1 Relative trend in landings per unit of effort of anglerfish by area, gear, year and quarter, 2003-2004, each series standardised to its mean.

[pic]

[pic]

Figure 3.3.1 Relative landings per unit of effort of anglerfish in the North Sea by gear, year and quarter, 2003-2004, each series standardised to its mean.

[pic]

Figure 3.3.2 Relative landings per unit of effort of anglerfish in the area West of Scotland by gear, year and quarter, 2003-2004, each series standardised to its mean.

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Figure 3.3.3 Relative landings per unit of effort of anglerfish in the Rock all area by gear, year and quarter, 2003-2004, each series standardised to its mean.

31. Danish data

The Danish LPUEs are based on logbook records. Figure 3.3.4 shows the trends in LPUEs for the main fisheries as mentioned in Sect. 2.2.2. Of relevance is the series for the demersal trawl fishery in the North Sea and in particular the series for this fishery in the Norwegian Deep as the fishery, where most anglerfish is taken. Note the upwards trend, especially from 2003 to 2004 for all fisheries and the subsequent stabilisation or even slight decline of the LPUE level in 2005. Similar patterns can be seen in time series for III A (Skagerrak).

The break observed for 2005, no longer increasing as in the previous years, could without any other information at hand be interpreted as a corresponding change in stock abundance in 2005. However, in view of other mainly qualitative indications of increasing stock abundance it is our opinion, that this discontinuation of the increase can at least to some extent be explained by the TAC constraint on the Danish fishery in the Norwegian EEZ from 2005. In the previous years the TAC for anglerfish in the North Sea had not been limiting the landings of this species, but in 2005 a TAC of 1800 t was negotiated for Danish landings from the Norwegian zone. According to the Danish fishing industry, this puts restrictions on the Danish catches of anglerfish in 2005. Note also the decline in North Sea landings from 2004 to 2005 reflecting the TAC for 2005. As a consequence it is highly probable that the observed decline in LPUE in 2005 based on logbook data merely reflects TAC constraints. The restrictions have continued in 2006, where a Danish TAC of 1750 t for the Norwegian EEZ has been agreed.

Figure 3.3.4. Logbook based estimates of LPUE by fishery.

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Table

År | Danish LPUE in IV (Kg/day) | Danish LPUE in | Danish LPUE in IIIa (Kg/day) |

dem trawl | Neph trawl | Shrimp trawl | Norwegian deeps (IVa) | dem trawl | Neph trawl | Shrimp trawl |

Mobile gears | Beam trawl | LARGE_BEAM SMALL_BEAM |

Demersal trawl & demersal seine | Bottom trawl | OTTER |

Danish & Scottish seiners | DEM_SEINE |

Pelagic trawl & Seiners | Pelagic Trawl | PEL_TRAWL |

Pelagic seiner & purse seiner | PEL_SEINE |

Dredges | DREDGE |

Passive gears | Longlines | LONGLINE |

Drift & fixed Nets except Trammel Nets | GILL |

Trammel Nets | TRAMMEL |

Pots & traps | POTS |

Gear type | Mesh size range |

Mobile gears | <16 |

16-31 |

32-54 |

55-69 |

70-79 |

80-89 |

90-99 |

100-119 |

>=120 |

Passive gears | 10-30 |

50-59 |

60-69 |

70-79 |

80-89 |

90-99 |

100-109 |

110-119 |

120-219 |

>=220 |

Histogram of Anglerfish weight density

Anglerfish kg/km2

Frequency

100

200

300

400

500

600

5

10

15

20

Median wdens