NOAA Technical Memorandum NMFS 

AUGUST 1983 

SOME DATA ON DOLPHIN MORTALITY IN THE 

EASTERN TROPICAL PACIFIC TUNA 

PURSE SEINE FISHERY PRIOR TO 1970 

Tim D. Smith 

Nancy C. H. Lo 

NOAA-TM-NMFS-SWFC-34 

U.S. DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric Administration 

National Marine Fisheries Service 

Southwest Fisheries Center 
NOAA Technical Memorandum NMFS 

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not appropriate or feasible Documents within this series, however, reflect sound professional work and 

may be referenced in the formal scientific and technical literature 
NOAA Technical Memorandum NMFS 

This TM series IS used for documentation and timely communication of preliminary results imterim reports, or 

Special Purpose informalion and have noi recwed complete formal review editorial control. or detailed editing 

AUGUST 1983 

SOME DATA ON DOLPHIN MORTALITY IN THE 

EASTERN TROPICAL PACIFIC TUNA 

PURSE SEINE FISHERY PRIOR TO 1970 

Tim D. Smith 

Nancy C. H. Lo 

Southwest Fisheries Center 

National Marine Fisheries Service, NOAA 

La Jolla, California 92038 

NOAA-TM-NMFS-S WFC-34 

U.S. DEPARTMENT OF COMMERCE 

Malcolm Baldrige. Secretary 

National Oceanic and Atmospheric Administration 

John V. Byrne. Administrator 

National Marine Fisheries Service 

William G. Gordon. Assistant Administrator for Fisheries 
CONTENTS 

INTRODUCTION..,..............,...................................... 

MATERIALS AND METHODS.............................................. 

RESULTS............................................................ 

DISCUSSION AND CONCLUSIONS......................................... 

LITERATURE CITED................................................... 

APPENDIX I. Letter from Gerald H. Lopes to Department of 

Conservation, Division of Fish and Game, 

Sacramento, California dated June 8, 1964........... 

APPENDIX 11. Letter from David W. Waller to Nancy C.H. Lo, 

Southwest Fisheries Center, dated June 25, 1979.. ... 

APPENDIX 111. Memorandum from William F. Perrin to Acting 

Laboratory Director, Tuna Resources Laboratory, 

dated September 8, 1966............................. 

APPENDIX IV. Memorandum from William F. Perrin to 

Director Fi shery-Oceanography Center, 

dated May 13, 1968.................................. 

Page 

1 

1 

2 

3 

5 

11 

15 

18 

23 

i 
LIST OF TABLES 

Tab1 e Page 

1 Number of dolphins killed, 

cauaht. and the use of "ba 

number of tons of 

kdown" on 21 Durs 

tuna 

sets invol vi ng dol phi ns, observed by Geral d Lopes 

in 1964, (Appendix 1) 6 

u- sei ne 

..................................... 

2 Numbers of dolphins captured and killed, by species, 

and tons of tuna caught, during 38 purse seine sets 

involving dolphins, observed by David Waller in 

...................................... 1964, (Appendix 11). 7 

3 Number of dolphins captured and number killed, tons 

of fish caught, and the duration of the set and of 

the "backdown" procedure on 28 purse seine sets 

i nvol vi ng dol phi ns, observed by Wi 11 i am Perrin in 

1966, (Appendix I11 and field notes) ...................... 8 

4 Number of dolphins captured and number killed, tons 

of fish caught, and use of "backdown" dolphin 

release procedure, on 15 purse seine sets involving 

dolphins, as observed by William Perrin in 1968, 

(Appendix IV and field notes) ............................. 9 

5 Mean (MI, standard deviations (SD) and number of set 

(N) for the total number of dolphins captured and 

killed, and the total tons of tuna caught in purse 

seine sets involving dolphins observed during four 

fishing trips in the 1960s. Mean numbers of dolphins 

killed are given for sets with >O ton tuna (termed 

successful and 0 ton tuna caught, (termed 

unsuccessful ); the proportions (PI of all sets 

during which the backdown dolphin-re1 ease procedure 

was used are also given ................................... 10 

ii 
SOME DATA ON DOLPHIN MORTALITY 

IN THE EASTERN TROPICAL PACIFIC TUNA 

PURSE SEINE FISHERY PRIOR 7'0 1970 

Tim D. Smith and Nancy C. H. Lo 

Southwest Fisheries Center 

National Mari ne Fi sheri es Service , NOAA 

La Jolla, California 92038 

INTRODUCTION 

Dolphins of severa species have been ki led incidentally in the eastern 

tropical Pacific tuna purse seine fishery since its beginnings in the late 

1950's (Perrin 1969, Smith 1983). Data have been collected by a number of 

i ndi vi dual s and agencies on many aspects of these mortal i ti es , i ncl udi ng 

numbers of dol phi ns kill ed and dol phin-re1 ease procedures used, but few data 

are available prior to 1970. As a result, the effect of the fishery on the 

dol phi n popul ati ons during that period i s uncertai n (Smith 1983). 

Here, what few data there are available for that period are presented. 

These data were collected by three individuals on four fishing trips, two in 

1964, and one each in 1966 and 1968. Tables of the observations made for each 

purse seine set are given. 

MATERIALS AND METHODS 

In 1964 Gerald Lopes, a member of the crew of a 340 ton tuna purse seine 

vessel , wrote a letter to the State of California, addressed to the Division 

of Fish and Game, describing his observations during those fishing trips. The 

vessel fished near Acapulco, Mexico apparently in the first half of the 

year. His letter is reproduced (retyped from a copy of his original) in 

Appendix I. He included a table listing the numbers of dolphins killed on 

several sets. 

Lopes noted in his letter that his counts were minimal , 'I. .. for the 

benefit of doubt." He described the procedures used during purse seining for 

tuna, including the dolphin re1 ease procedure termed "backdown" or "backing 
2 

down." He indicated the sets in which this release procedure1 was used. He 

did not indicate the species of either the tuna caught or the dolphins killed. 

In 1979 David Waller wrote a letter to National Marine Fisheries Service, 

addressed to N. Lo, in response to our inquiry if he had any information about 

dolphin mortalities during the 1960s. A typed version, from his hand written 

original letter, is reproduced in Appendix 11. Waller accompanied the crew of 

a 350-ton capacity purse seiner on several fishing trips in the 1960s while he 

was a graduate student at the University of Wisconsin. He included a hand 

written table with his letter of 1979, also in Appendix 11, giving details of 

his observations of 46 purse seine sets made during February and March of 

1964. He gives numbers of dolphins captured and killed in each net set, 

classified to species of dolphin (spotted = Stenella attenuata, spinner = S. 

longirostris), tons of tuna caught, and date of the set, as well as othzr 

details of the operations aboard ship. Waller did not indicate the location 

of the fishing activity, and the data apparently include some sets not 

involving dolphins (numbers 1, 3, 6, 12, 14, 15, 19, and 20, indicated in the 

original by a zero crossed with a horizontal line). 

In 1966 and 1968 William Perrin, a biologist with the Southwest Fisheries 

Center, observed dolphin mortalities aboard two fishing trips on different 

vessels. He recorded extensive data on a variety of aspects of the tuna purse 

seining process; his records are on file at the Southwest Fisheries Center. 

Although observing dolphin mortality was not the primary goal of his field 

work , Perri n recorded data on dol phi n mortal i ty. 

Perrinls first observations were made aboard a 331-ton capacity tuna 

purse seine vessel , operating generally in the area 8" to 13"N latitude and 

90" to 95"W longitude in July and August 1966. He recorded estimates of the 

number of dolphins captured in most sets, and of the numbers killed in five 

sets, when large numbers were killed. He indicated (personal communication) 

that some dolphins were killed on every set. 

Perrin's second obervations were made aboard a 300-ton capacity vessel 

operating in the area 7" to 8"N latitude and 90" to 92"W longitude in April 

1968. He recorded the number of dolphins killed in all sets involving 

dolphins and observed one set not involving dolphins. He a1 so recorded the 

duration of the backdown procedure, when used, as well as the total duration 

of the set. 

RESULTS 

Lopes' letter provides data on the number of dolphins killed, tons of 

tuna caught, and on use of the backdown dolphin-release procedure in 21 

dolphin sets in 1964 (Table 1). An average of 61 dolphins was killed per set, 

with an average catch of 9 tons of tuna. Backdown was used on 81% (17 of 21 

sets) of the sets (Table 5). 

*For a full description of the 

to release dolphins while reta 

"backdown" procedure used by tuna purse 

ning the tuna catch, see Coe and Sousa 

seiners 

1972). 
Waller's letter provides data on the number of all dolphins captured, the 

number of dolphins killed by species, and the tons of tuna caught in 38 

dolphin sets in 1966 (Table 2). An average of 81 dolphins was captured per 

set, with 25 being killed, and with an average catch of 7 tons of tuna. No 

backdown information was recorded (Table 5). 

Perrin's records on 28 dolphin sets observed in 1966 give the number of 

dolphins captured by species and tons of tuna caught (Table 3). While 

dolphins were killed in all sets involving dolphins, the number killed was 

recorded for only 5 sets. The duration of the backdown dolphin-release 

procedure and of the total set is given. An average of 582 dolphins and 12 

tons of tuna was captured per set. The mean number of dolphins killed is 250 

per set. This is a biased estimate because Perrin recorded data for sets with 

only large numbers of dolphins killed. The time spent backing down averaged 8 

minutes for 14 sets; backing down was used in 90% (18 of 20 sets) of the sets 

where information is available (Table 5). 

Perrinls records for 15 dolphin sets observed in 1968 give total numbers 

of dolphins captured, numbers of dolphins killed by species, tons of tuna 

caught, and the use of backdown (Table 4). An average of 402 dolphins was 

captured and 113 killed per set, with 21 tons of tuna caught. Backdown was 

used on 92% (11 of 12 sets) of the sets where information is available 

(Table 5). 

For the data collected from these four trips, the mean number of dolphins 

captured varied markedly from less than 100 to nearly 600, with an overall 

average of 284 animals (Table 5). The mean number of dolphins killed for sets 

with a ton or more of tuna2 (successful) varied from 26 to 250, with an 

overall mean of 69, and a standard deviation of 87. The highest value is froin 

Perri n Is 1966 observations, where only ki 11 s for sets with 1 arger mortal i ti es 

were recorded. If the 1966 observations are excluded, the overall 

kill-per-set is 56 with a standard deviation of 70. The average tons of tuna 

caught ranged from 7 to 21 tons for all sets, with an overall average of 11. 

The standard deviation is 13. 

DISCUSSION AND CONCLUSIONS 

Available data on numbers of dolphins killed during tuna purse seine net 

sets in the 1960s are limited to four fishing trips. The data were collected 

by different investigators and was, in some cases, incomplete. Unfortunately, 

these data were not collected for years prior to 1964, before new fishing 

techniques were implemented that were designed to reduce dolphin kills. 

The frequency of use of the "backdown" dol phi n-re1 ease procedure within 

fishing trips increased over time, but no information is available prior to 

1964. The variability of the use of this procedure among vessels cannot be 

2The catch of tuna was generally recorded to the nearest ton; a value of zero is 

assumed to mean that less than 1/2 ton was caught. 

for l'successful 

Other definitions have been used 

sets, where different data recording conventions have been used. 
4 

assessed from these data. 

Despite the several shortcomings, these data are all that are presently 

available to us. Some additional data, however, appear to exist. Waller, in 

his letter (Appendix II), notes that he holds some additional data which ". .. do not differ much from the trends shown in the enclosed material". 

Similarly, the Inter-American Tropical Tuna Commission holds data from two 

fishing trips in that period which include data on numbers of dolphins killed 

(R. Allen, pers. commun.). Allen noted that his data are not markedly 

different from those which are reported here but cannot be released at this 

time because of confidential agreements with the vessels' captains. 
5 

LITERATURE CITED 

Coe, J. M. and G. Sousa. 1977. Removing porpoise from a tuna purse seine. 

--- Mar. Fish. Rev. 34(11-12):15-15. 

Perrin, W. F. 1969. Using porpoise to catch tuna. World Fishing, 

18(6):42-45. 

Smith, T. D. 1983. Changes in size of 3 dolphin populations in the eastern 

tropical Pacific -- Fish. Bull. U.S. 81(1):1-14. 
6 

Table 1. Number of dolphins killed, number of tons of tuna caught, and the use of "backdown" on 21 purse seine sets involving 

dolphins, observed by Gerald Lopes in 1964, (Appendix I). 

Set Number of Tons of tuna " B a c k down I' 

number1 dol phi ns ki 11 ed2 caught used3 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

30 

69 

20 

46 

30 

68 

6 

26 

12 

60 

12 

60 

40 

115 

153 

76 

18 

60 

150 

> 1004 

78 

6 

7 

15 

7 

7 

1 

4 

2 

7 

6 

0 

23 

3 

5 

4 

5 

60 

14 

12 

2 

a 

Y 

N 

Y 

Y 

N 

Y 

Y 

Y 

Y 

Y 

Y 

Y 

Y 

Y 

Y 

Y 

N 

Y 

Y 

Y 

N 

lSequence number of sets in letter (Appendix I) 

2Mi ni mal estimates 

3Y = yes, N = no 

'+In computing kill rates, e.g. kill/set, the average 

kill of sets with over 100 kills was used (=139). 
7 

Table 2. Numbers of dolphins captured and killed, by species, and tons 

of tuna caught, during 38 purse seine sets involving dolphins, 

observed by David Wal ler in 1964, (Appendix 11). 

-------------- Number of Dol phi ns------------- 

numb e r 1 Cap tured2 spotted spinner total caught 

Killed Tons 

Set ............................... of tuna 

2 

4 

5 

7 

8 

9 

10 

11 

13 

16 

17 

18 

21 

22 

23 

24 

25 

26 

27 

28 

29 

30 

31 

32 

33 

34 

35 

36 

37 

38 

39 

40 

41 

42 

43 

44 

45 

46 

500 

30 

300 

75 

50 

40 

100 

25 

50 

65 

50 

20 

7 

60 

150 

30 

80 

50 

40 

40 

100 

140 

50 

80 

65 

40 

90 

225 

40 

160 

80 

50 

50 

65 

30 

20 

20 

25 

150 

19 

41 

26 

38 

11 

45 

2 

37 

14 

10 

13 

4 

3 

20 

23 

14 

3 

6 

20 

24 

68 

16 

6 

23 

7 

7 

30 

2 

36 

20 

25 

10 

7 

5 

2 

1 

16 

0 

0 

0 

0 

0 

0 

14 

0 

0 

0 

0 

0 

0 

24 

8 

0 

0 

3 

20 

0 

0 

14 

0 

0 

5 

0 

0 

0 

0 

33 

7 

0 

0 

5 

0 

0 

0 

0 

150 

19 

41 

26 

38 

11 

59 

2 

37 

14 

10 

13 

4 

27 

28 

23 

14 

6 

26 

20 

24 

82 

16 

6 

28 

7 

7 

30 

2 

69 

27 

25 

10 

12 

5 

2 

1 

16 

33 

7 

5 

7 

6 

1 

10 

0 

15 

13 

10 

4 

7 

1 

7 

6 

5 

1 

0 

7 

6 

19 

3 

1 

3 

2 

3 

8 

2 

31 

4 

10 

1 

4 

16 

1 

0 

5 

ISequence number given in letter (Appendix 11), with sets 

20nly total indicated. 

not i nvol vi ng dol phi ns omi tted. 
8 

Table 3. Number of dolphins captured and number killed, tons of fish caught, and the duration 

of the set and of the "backdown" procedure on 28 purse seine sets involving dolphins, 

observed by William Perrin in 1966, (Appendix I11 and field notes). 

-------------- Number of Dolphins--------------- 

Captured 

Killed Tuna Caught Durations (min) Set ................................. number1 spotted spinner total total (tons) Backdown Set 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

26 

27 

28 

29 

-2 

- 

- 

- 

- 

250 

900 

250 

37 5 

665 

450 

270 

7 50 

750 

150 

375 

140 

200 

350 

400 

495 

1100 

1000 

- 

- 

- 

- 

- 

- 

- 

0 

- 

- 

750 

100 

250 

125 

35 

150 

30 

250 

250 

350 

125 

10 

0 

0 

0 

55 

0 

0 

- 

- 

- 

- 

- 

- 

1000 

1000 

500 

500 

700 

50 

600 

1000 

300 

1000 

1000 

500 

100 

500 

300 

150 

200 

350 

400 

550 

1100 

1000 

- 

+3 

+ 

+ 

+ 

+ 

300 

+ 

+ 

300 

+ 

+ 

+ 

150 

350 

+ 

+ 

+ 

150 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

0 

10 

4 

5 

3 

10 

40 

13 

7 

70 

22 

2 

16 

40 

8 

8 

13 

6 

3 

5 

5 

6 

11 

11 

14 

52 

33 

- 

- 

- 

- 

- 

10 

9 

11 

11 

8 

9 

- 

04 

- 

+3 

9 

10 

+ 

+ 

6 

+ 

a 

5 

5 

6 

6 

0 

- 

- 

- 

95 

54 

103 

95 

119 

90 

131 

154 

90 

140 

100 

127 

144 

97 

175 

122 

100 

113 

104 

90 

68 

122 

117 

412 

240 

- 

- 

1Sets not involving dolphins omitted; sequence number as per field data. 

*- = no observation recorded 

3+ = greater than zero, but amount not recorded 

4O = backdown procedure not used 
9 

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11 

APPENDIX I. 

Letter from Gerald H. Lopes to Department of Conservation, Division of Fish and 

Game, Sacramento, California dated June 8, 1964. Portion unclear is marked by *. 
12 

Rt. 1, Box 64 

Patterson, Calif. 

June 8, 1964 

Dept. of Conservation 

Division of Fish and Game 

Sacramento, Cal if 

Dear Sirs: 

I have just recently completed two trips aboard one of San Diego's famed 

commercial tuna boats. Our first trip lasted forty-four days, and the second 

thirty-four. The grounds we fished were about 200 miles off the coast of 

Acupulco. At this time of year the weather there is very warm and pleasant 

with the water ranging over 80 degrees. 

The trip did much for me as far as nourishing my physical aspects. It 

also gave me much "food for thought." 

To start with, the ship "Concho'l which I was aboard was a sleek 118 foot 

purse seiner equipped with a net485* fathoms long and 46* fathoms deep. The 

boat has thirteen refrigerated "wells" with capacities ranging from 15 to 40 

tons each. With a full load she is supposed to carry 340 tons of fish, though 

the two trips only totaled 318 on our first and 308* on the other. 

When working in lower murky waters (around Chile and Peru), I am told 

that all of the sets are made directly on schools of running tuna. But while 

working in clear waters, such as the fishing grounds off Acupulco, the boats 

practically always act on schools of porpoise which the majority of the time 

have tuna that school directly below them for some unknown reason. On our two 

trips we had a total of 110 sets. Of these only four were on school fish. 

Upon approaching one of these schools a person usually notices a large 

"spot" of birds. As you get closer, you can see porpoise, fish and birds in 

one big "feeding frenzy." The boat will run with them for awhile to check if 

there is enough fish with the porpoise to make it worth while for a "set." 

When it is determined a set is feasible, the ship stops and lowers its 

two outboard powered speedboats. Once the speedboats or "pongas" (as they are 

called) are in the water the ship again gets underway. The pongas run with 

the ship as it circles the school, each time tightening the circle until it 

gets into position to make the set. When the word is given, the seven ton 

skiff hauled on the rear of the ship is "cut loose" taking one end of the net 

and begins towing (or rather holding the net) as the ship encircles the 

school. At the same time the skiff is turned loose, the two pongas are given 

commands by radio head sets. One ponga goes to the stern and back around the 

wake, while the other goes ahead and forward of the boat. The idea is to get 

all the porpoise into the net, as the tuna will stay right with them. Many 

times, if just several of the porpoise escape, the whole school of tuna will 

go with them. 
13 

With the circle completed, the ship will meet the skiff and pick up the 

end of the net. From here the net will be pursed. This is done by a ''purse 

line." A cable threaded through rings attached to the bottom of the net. 

When the cable is all brought in, the rings and the bottom of the net are all 

brought on deck. From here there is not a chance of the fish (or porpoise) to 

escape. 

From here the net is begun to be brought in. This is done by means of a 

large ''power block." The power block, attached to a boom, reels the net in 

and enables it to be stacked on board again. Usually before the net is half 

way in porpoise begin to appear, wrapped or tangled in the net. These are 

taken out on board and thrown over the other side. Most are cut and bleeding 

from the punishment of the net, many are already dead from drowning. 

Usually when the net is about half way in, it is tied up. The ship is 

then put in reverse. This is known as backing down. This causes the net to 

float towards the bow where the corks sink at the center of the net and enable 

most of the porpoise to ''go cut over the corks'' without the fish escaping. 

But there is always that ten or fifteen percent that can't find their way out. 

The net is then untied and the stacking continues. Now there are both 

fish and porpoise coming up the net. By this time (perhaps 1 hour) you notice 

only an occasional porpoise that is still alive. The net is brought in as far 

as possible until all fish and porpoise are in a "sack." The skiff then 

arrives at the edge of the sack and the corks are tied to it. 

If there are still an abundance of porpoise in the net, several men will 

crawl into the net and take them out. By this time, perhaps only five out of 

fifteen still remain alive. 

On the trips 110 sets were made. Sometimes we missed porpoise and all. 

Sometimes we just got porpoise. Other than school fish, whenever we got fish, 

we always had porpoise. This leaves me with grave concern. Will this cause 

depletion or perhaps an extinction of porpoise? Is there anything that can be 

done about it? 

I have mentioned it to many of the men aboard the "Concha," even the 

Most of them say that it is a shame, the slaugh-at is going 

Others shrug it off, as if to say 'lit's a living." 

skipper. 

on. 

I have tried to get an estimate on the kill of porpoise on several 

sets. I would have gotten more, but my work kept me from keeping track. The 

tonnage here is pretty accurate, but the porpoise count is less for the 

benefit of doubt. 

6 

7 

15 

7 

7 

tons of tuna w/backdown-- 30 porpoise killed 

tons of tuna w/o backdown-- 69 porpoise killed 

tons of tuna w/backdown-- 20 porpoise killed 

tons of tuna w/backdown-- 46 porpoise killed 

tons of tuna w/o backdown-- over 100 porpoise killed 
14 

1 

4 

2 

7 

6 

0 

23 

3 

5 

4 

5 

60 

14 

8 

12 

2 

ton of tuna w/backdown-- 30 porpoise killed 

tons of tuna w/backdown-- 68 porpoise killed 

tons of tuna w/backdown-- 6 porpoise killed 

tons of tuna w/backdown-- 26 porpoise killed 

tons of tuna w/backdown-- 12 porpoise killed 

tons of tuna w/backdown-- 60 porpoise killed 

tons of tuna w/backdown-- 78 porpoise killed 

tons of tuna w/backdown-- 12 porpoise killed 

tons of tuna w/backdown-- 60 porpoise killed 

tons of tuna w/backdown-- 40 porpoise killed 

tons of tuna w/backdown-- 115 porpoise killed 

tons of tuna w/o backdown-- 153 porpoise killed 

tons of tuna w/backdown-- 76 porpoise killed 

tons of tuna w/backdown-- 18 porpoise killed 

tons of tuna w/backdown-- 60 porpoise killed 

tons of tuna w/o backdown-- 150 porpoise killed 

You'll notice that I have noted some with backdown and some without. 

Porpoise will not go out of the net after dark and sometimes the skipper got 

lazy, I guess. These 21 sets totaling 198 tons, killed 1229 porpoise (at 

least). That comes to over six porpoise per ton. Six times 300 is 1,800 

porpoise. There are thirteen other boats just in this same company. By the 

time each boat makes just one trip the porpoise population drops 25,200. 

Quite an unbelievable figure. How long can this go on? Perhaps a new net or 

a modification to the ones they are now using is the solution. 

Another situation which brought question to qy mind was the legal size of 

the fish taken. Using a net which can cover a diameter of almost a quarter of 

a mile, how can a person determine the size of fish it will yield? 

Yellowfin tuna are found in the fishing grounds off Acupulco. But many 

times skipjack, a smaller tuna, are found in the schools with them. To be 

legal, skipjack must weigh at least 4 pounds (or so I've been told). During 

our trips we must have thrown overboard several tons. I also saw several 

large yellowfin thrown overboard because they were too large. What good can a 

dead fish be at the bottom of the sea? Is it fish and game laws or just 

because the canneries would rather not take the trouble to process them? 

These are questions that bear looking into. In my concern with this 

subject, I would be more than happy to help you in anyway you may see fit. 

I may be reached through mail at Rt. 1, Box 64, Patterson, California, or 

by telephone at TY1 er 2-3944. 

Thank you, 

s/Gerald H. Lopes 

Gerald H. Lopes 
15 

APPENDIX 11. 

Letter from David W. Waller to Nancy C.H. Lo, Southwest Fisheries Center, dated 

June 25, 1979. 
16 

Laredo, Texas 

Monday 25 June 1979 

Dr. Nancy C. H. Lo, Leader 

Quantitative Analysis Task Group 

National Marine Fisheries Service 

Southwest Fisheries Service 

La Jolla, California 92038 

Dear Dr. Lo: 

I am enclosing copies of some of my records of the first 1964 excursion 

of the Independence which I observed on board. They cover the period 

February-March and include detail reports on the first 24 of all 56 sets made, 

and a summary sheet which shows abstracted data from the first 46 of the 56 

sets. 

The other information is available, but I did not have a chance to 

complete the records to send to you before leaving for my current work with a 

group of KSU students in our Mexican, Field Biology course. In fact, I'm 

sending these from our campground at Laredo. We enter Mexico tomorrow for a 

two-week excursion. 

I will prepare the rest of the records to send to you after July 20. The 

data do not differ much from the trends shown in the enclosed materials. This 

will just have to do for now. 

Hasta la regressa, 

David W. Waller 

Assistant Professor 
17 

ADDITIONAL NOTES 

106 = Total Encounters of' c' Porpoises 

56 = Total Number of Sets 

Mortal i ty Cum. Cum. 

Date Set Tuna spot Spin Spot Spin Tags tuna PorP We1 1 

Feb 20 1 

22 2 

22 3 

22 4 

26 5 

27 6 

28 7 

28 8 

28 9 

Mar 1 10 

3 11 

3 12 

4 13 

4 14 

4 15 

6 16 

6 17 

6 18 

7 19 

8 20 

8 21 

8 22 

9 23 

9 24 

10 25 

10 26 

10 27 

11 28 

12 29 

12 30 

12 31 

13 32 

13 33 

14 34 

14 35 

15 36 

16 37 

16 38 

18 39 

19 40 

20 41 

20 42 

20 43 

21 44 

21 45 

22 46 

0 

33--5 (500) 

0 

7 

5 

0 

7 

6 

1 

10 

0 

0 

15 

0 

0 

13 

9.5 

3.5 

0 

0 

6.5 

.5 

7--25 

6 

5 

.75 

0 

7 

6 

19 

2.5 

1 

3 

1.5 

2.5 

8 

1.5 

30.5 

4 

10 

1 

3.5-1.5 

16 

1 

0 

5 

30 

300 

75 

50 

40 

20 

50 

65 

50 

20 

7 

30 

140 

30 

80 

10 

20 

40 

100 

120 

50 

80 

50 

40 

80 

225 

40 

125 

50 

50 

50 

40 

30 

20 

20 

25 

0 

0 

0 

(100) 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

5 

0 

0 

0 

0 

0 

30 

10 

0 

0 

40 

20 

0 

0 

20 

0 

0 

15 

0 

(10) 

0 

0 

35 

30 

0 

0 

25 

0 

0 

0 

0 

150 

19 

41 

26 

38 

11 

45 

2 

37 

14 

10 

13 

4 

3 

20 

23 

14 

3 

(6) 

20 

24 

68 

16 

6 

23 

7 

7 

30 

2 

36 

20 

25 

10 

7 

5 

2 

1 

16 

0 

0 

0 

0 

0 

0 

14 

0 

0 

0 

0 

0 

0 

24 

8 

0 

0 

3 

(20) 

0 

0 

14 

0 

0 

5 

0 

0 

0 

0 

33 

7 

0 

0 

5 

0 

0 

0 

0 

0 

0 

0 

1 

15 

0 

0 

0 

4 

0 

5 

0 

3 

0 

0 

0 

2 

0 

0 

0 

0 

0 

3 

4 

4 

2 

0 

8 

0 

0 

0 

8 

0 

2 

1 

1 

1 

0 

8 

6 

6 

2 

3 

3 

5 

8 

33.5 

33.5 

40.5 

45.5 

52.5 

58.5 

59.5 

69.5 

69.5 

89.5 

97.5 

107. 

110.5 

117. 

117.5 

124.75 

130.75 

136.75 

137.5 

137.5 

144.5 

150.5 

169.5 

172. 

173. 

176. 

177.5 

180. 

188. 

189.5 

210. 

214. 

224. 

225. 

230. 

246. 

247. 

247. 

252. 

150 

150 

169 

210 

236 

274 

285 

344 

346 

383 

397 

407 

420 

424 

45 1 

479 

502 

516 

522 

548 

568 

592 

674 

690 

696 

724 

73 1 

738 

768 

7 70 

839 

866 

891 

901 

913 

918 

920 

921 

93 7 

P-5,S-5 

5-5 

5-5 

S-5,S6 

5-6 

5-6 

S-6, P-6 

P-6 

P-6, P-4 

P-4, s4 

P-4, s4 

P-4, s4 

s-4, s3 

s-4, s3 

53 

53 

53 

53 

s3, P3 

P3 

P3 

P3 

P3, P2 

P3, P2 

P2 

P2 

P2 

P2, s2 

P2, s2 

s2, P1 

P1 

Ply s1 

Ply s1 

Ply s1 

51 

51 

~~~~~~ ~~ ~ 

M/V -- U.S. 14 tons Y.F. - on spotters 
18 

APPENDIX I I I. 

Memorandum from William F. Perrin to Acting Laboratory Director, Tuna Resources 

Laboratory, dated September 8, 1966. 
19 

Acting Laboratory Director, 

Tuna Resources Laboratory, La Jolla, Calif. 

September 8, 1966 

W. F. Perrin, Biological Technician (Fish. 1 

Cruise on M/V Conte Blanco 

Introduction: The following is a brief summary of my activities aboard the 

purse seiner Conte Blanco on a cruise from 10 July to 11 August 1966. Fishing 

operations wemarriedout along the coast of Mexico south to the Gulf of 

Tehuantepec and in an area centered on 10" north latitude and 90' west 

1 ongi tude. 

The Vessel: The Conte Blanco is a 117 ft. purse seiner with a capacity 

of 331 t ons. She carma525x 42 fathom net and is equipped with four 

"porpoise chaser'' skiffs in addition to the large seine skiff. 

Set Logs: A standard set log sheet was completed for each set. A 

total of 29 sets were made of which 28, all made on porpoise, were successful, 

yielding a mean catch of approximately 11 tons per set. The largest haul was 

55 tons and the smallest 250 lbs. 

Bathykmographs: Four BKG's were taken on the cruise. One was lost on set 

* two more were lost on set #3. The remaining instrument was lost on set $6. A total of 14 usable traces were obtained. 

Blood Samples: A total of 155 yellowfin and 30 skipjack blood samples were 

taken, from 8 hauls. The samples were centrifuged and the serum frozen and 

retained until return to San Diego where it was turned over to Izadore Barrett 

of the IATTC. 

Sharks: Two net-eater sharks (C. malpeloensis) were tagged and 

released. The captain ordered a hault put to tagging operations when a 

crewman was severely bitten on the hand. Twelve net-eaters were measured and 

sexed. Nine individuals were examined for stomach contents. One large manta 

ray was measured, tagged and released. A whale shark was sighted and 

photographed. 

Weather: A total of 39 standard international weather reports were 

compiled and logged. Of these, 25 were successfully transmitted to the 

weather observer in San Francisco thru KM1. A continuous barograph record of 

pressure was kept. 

Stomach samples: Yellowfin stomach samples were taken on three hauls. A 

total of /5 , about 25 per haul, were taken. 
20 

Acting Laboratory Director -2- September 8, 1966 

Net Data: The history of and peculiarities of operation and 

construction of the seine on the Conte Blanco were investigated and 

recorded. A scale diagram of the net ismg prepared. 

Photos : 150 black and white and 75 color photos were taken of 

mg operations. In addition, 350 feet of 16 mm movie film was exposed. 

Suggestions : It is suggested that the following items of equipment be 

taken along on future cruises: 

1. More film: Film is cheap compared to manhour expense and takes 

up little room. Good shots are often missed because of a 

reluctance to use up the film too rapidly. 

2. Polaroid filters: This item is essential if good results are to 

be obtained when shooting down into the water. 

3. High-powered binoculars: for better observation of behavior of 

birds, tish and cetaceans. 

4. Spare literature, reprints, etc. to give to interested crew 

members. 

Species Encountered: The following species were observed in the net hauls: 

Elasmobranchs: Net-eater shark Carcharhinus malpeloensis 

Manta, Manta sp. 

Hamme rhTSFy rtia zy ga e n a 

Blue shark, meTeleosts: Ye1 1 owfi n tuna, Thunnus a1 bacares 

Skipjack, Euthynmamis 

Bullet mackerel, Auxis sp. 

Black skipjack, Euthynnus lineatus 

Swordf i s h , Xi p hi as gl adi us 

- 

Remoras, Remora remora 

Phtheir7TFiVFs 1 ineatus 

Ribbonfish, Lu cri status 

Uni dent i f i ecarangi d 

Unidentified hemi ramphid 

Spotted dolphin, Stenel la graffmani 

"spinner" dolphin, Stenella microps and/or longirostris 

Pacific bottlenose dolphin, Tursiops sp. 
21 

Acting Laboratory Director -3- September 8, 1966 

Repti 1 es : Green turtle, Chelonia agassizii 

Yellow-bellied Seasnake, Palamis platurus 

In addition the following animals were sighted and are considered of 

sufficient importance to be mentioned: 

Whale shark, Rhincodon typus, (photographed) 

Baird's dolphin, Delphixairdii 

Killer whale. Orcinus orca 

William F. Perrin 

WFP:md 

Admi n 

Chron 

W. F. Perrin 
22 

SET POSITION DATE SPIN SPOT SER YELLOWFIN 

W N 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

26 

27 

28 

29 

114: 30 

107: 35 

101 : 10 

98: 35 

98: 27 

93: 13 

92: 51 

92: 21 

92: 29 

92: 15 

92:OO 

92: 30 

91:20 

91:oo 

90: 55 

91:08 

90: 48 

90: 48 

91:54 

91:57 

91:02 

90: 30 

90: 30 

91:40 

91:36 

91: 28 

91:30 

89:04 

88: 48 

26: 52 

21:35 

17: 10 

16 : 02 

16: 03 

12: 50 

12: 17 

12: 13 

12:Ol 

11:38 

11:07 

11: 29 

11:33 

11:08 

10: 51 

10:40 

10: 30 

10: 24 

10: 00 

10: 03 

9: 00 

8: 50 

8: 40 

9: 12 

9: 20 

9: 14 

9: 27 

8: 20 

8: 31 

7-11 

7-14 

7-16 

7-17 

7-17 

7-19 

7-19 

7-20 

7-20 

7-20 

7-21 

7-21 

7-21 

7-22 

7-22 

7-23 

7-23 

7-24 

7-25 

7-25 

7-27 

7-27 

7-27 

7-28 

7-28 

7-29 

7-29 

8-1 

8-2 

0 0 

X X 

X X 

0 X 

X X 

4/ 5 1/5 

7 50 250 

(300 Killed) 

X X 

100 900 

250 250 

(300 Killed) 

125 375 

35 66 5 

X X(most) 

150 450 

(150 Spin Killed) 

(300-400 Ki 11 ed) 

30 270 

250 750 

250 750 

350 150 

(150 Killed) 

100 Total 

125 375 

300 Total 

1000 

10 140 

0 200 

0 350 

0 400 

55 49 5 

0 1200 

0 1000 

0 

1/8 

10 

2 1/2 Y, 1/2 SK 

5 

3 

10 

4 

13 

7 (+lo lb SK) 

7 (+lo lb SKI 

22 (+lo lb SK) 

2 

16 (+50 lb SK) 

40 (+ZOO lb SK) 

8 (+lo0 lb SK) 

8 (+ZOO lb SK) 

13 

6 

2 1/2 

5 

(-) 

5 

6 (+6 lb SK) 

11 

11 

14 (+5 lb SK) 

52 

33 
23 

APPENDIX IV. 

Memorandum from William F. Perrin to Director Fishery-Oceanography Center, 

dated May 13, 1968. 
24 

TO: 

FROM: 

SUBJECT: 

Vessel : 

Per sonne 1 : 

Dura t i on : 

Di rector 

Fi shery-Oceanography Center 

Fishery Biologist (General ) 

Operations Research Program 

File: 3201.3 

DATE: May 13, 1968 

CRUISE REPORT - M/V Carol Virginia (commercial tuna seiner) 

M/V Carol Virginia (commercial tuna seiner) 

wi 1 liam. Perri n 

1 April 1968 to 29 April 1968 

Fishing operations were carried out mostly in the area of 7 and 8"N latitude 

and 90 and 92"W longitude, 300-400 miles offshore. 

Data and specimens were gathered for the following areas of research: 

1. Variation in rostrum length in Stenella longirostris from the Eastern 

2. Comparative feeding habits of ye1 1 owfi n tuna (Thunnus a1 bacares ) and 

3. Intra-and interschool morphometric variation in the Eastern Pacific 

4. The ontogeny of color pattern in the Eastern Pacific spotted porpoise 

5. Color pattern and sexual dimorphism in Stenella longirostris from the 

Central Pacific, and the taxonomic status of Stenella microps. 

porpoise (Stenella graffmani and - S. longirostris) in mixed-species schools. 

spotted porpoise ( Stenel 1 a graffmani 1. 

( Stenel 1 a graffmani ). 

Eastern Central Pacific. 

6. Interschool differences in the distribution and abundance of internal 

parasites in two schools of the Eastern Pacific spotted porpoise (Stenella 

araffmani 1. 

7. Predation by the tuna fishery on two species of porpoise (Stenella 

longirostris and - S. graffmani) in the Eastern Central Pacific. 

8. Occurrence of suckerfish (Remorz remora) on the Eastern Pacific spotted 

porpoise (Stenella graffmani 1. 

9. Behavior of porpoise (Stenella longirostris and - S. graffmani) before and 

during a tuna seine set. 

10. Sex and size structures of schools of the Eastern Pacific spotted 

porpoise (Stenel la graffmani 1. 

11. The "porpoise factor" in tuna seining. 
25 

12. Preliminary investigation of serum and eye protein polymorphisms in the 

Eastern Pacific sotted porpoise. 

Si xty-si x specimens of the Eastern Paci f i c spotted porpoi se, (Stenel 1 a 

graffmani), from ‘2 schools, were brought back in the fish wells and placed in 

cold storage. After being processed for the above areas of investigation this 

material will be placed in the new cetacean depository at the U. S. National 

Museum. 

The cruise can be considered to have been successful, due primarily to 

extensive and freely-given cooperation by the owners, captain and crew of the 

vessel. 

William F. Perrin 
26 

Table 1. Mortality of porpoise during tuna-seining operations in 

the eastern tropical Pacific. Results of 15 net-sets 

made during April 1968. 

Estimate of 

Ye1 lowfin Spotters Spinners proportion of 

tuna (Stenella graffmani (S. - longirostris) school killed 

Set no. (tons) (no. 1 (no. ) (%I 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

0 

6 

0 

9 

10 

35 

45 

60 

50 

35 

10 

2 

15 

5 

30 

1 

55 

4 

33 

31 

310 

268 

92 

185 

39 

34 

48 

34 

0 

239 

0 

78 

3 

1 

9 

75 

0 

0 

0 

20 

0 

0 

0 

109 

33 

<1 

35 

<5 

15 

15 

25 

25 

10 

30 

15 

20 

15 

10 

20 

50 

Total 312 1359 338 Average=19.4% 

Total = 1697 porpoise 

1697 porpoise 

312 tons of YF 

-------------- = 5.45 porpoise per ton 
'I 

'. 

RECENT TECHNICAL MEMORANDUMS 

Copies of this and other NOAATechnical Memorandums are available from the Nattonal Technical 

Information Service, 5285 Port Royal Road, Springfield. VA 221 67 Paper copies vary in price Microfishe copies cost $3 50 Recent issues of NOAATechnical Memorandumsfrom the NMFS Southwest 

Fisheries Center are listed below 

NOAA TM-NMFS SWFC 24 

25 

26 

27 

28 

29 

30 

31 

32 

33 

Revised update and retrieval system for the CalCOFl oceanographic data file. 

L. EBER and N. WlLEY 

(December 1982) 

A preliminary study of dolphin release procedures using model 

.purse seines. 

D. 6. HOLTS and J. M. COE 

(December 1982) 

"Possible effects of sampling biases on reproduction rate estimates 

T. POLACHECK 

(January 1983) 

"Reports of porpoise experiment testing detection of on-track 

R. S. HOLT 

(February 1983) 

"Two computer programs to project populations with time-varyinrl 

for porpoise in the eastern tropical Pacific." 

schools (pet dots), March 7-April 5, 1981 ." 

vital rates." 

T. GERRODETT'E, D. GOODMAN ti, J. EARLOW 

(February 1983) 

Report of eastern tropical Pacific research vessel marine mammal 

R. S. HOLT 

(March 1983) 

Estimating age of spotted and spinner dolphinsfStenella attenuata 

A. C. MYRICK. JR., A. A. HOHN, P. A. SLOAN, M. KIMURA 

(April 1983) 

Re-estimation of three parameters associated with anchovy 

egg and larval abundance: Temperature dependent incubation 

time, yolk-sac growth rate and egg and larval retention in 

mesh nets. 

N. C. H. LO 

(May 1983) 

survey. May 15-August 3, 1982. 

and Stenella longirostris) froni teeth. 

and D. D. STANLEY 

"NMFS guidelines on economic valuation of marine recreational 

D. D. HUPPERT 

(June 1983) 

fishing" 

"Summary of environmental and fishing information on Guam and 

the Northern Mariana Islands: A review of the plankton 

communities and fishery resources of Guam and the Commonwealth of the Northern Mariana Islands" 

R. N. UCHIDA 

(July 1983) 

_i_ PA I . ....-I