# New information from fish diets on the importance of glassy flying squid (Hyaloteuthis pelagica) (Teuthoidea: Ommastrephidae) in the epipelagic cephalopod community of the tropical Atlantic Ocean

Yves Cherel, Marc-Richard Sabatié, Michel Potier, Francis Marsac, Frédéric Ménard

<figure><img src="image_1.png" /></figure>

## ► To cite this version:

Yves Cherel, Marc-Richard Sabatié, Michel Potier, Francis Marsac, Frédéric Ménard. New information from fish diets on the importance of glassy flying squid (Hyaloteuthis pelagica) (Teuthoidea: Ommastrephidae) in the epipelagic cephalopod community of the tropical Atlantic Ocean. Fishery Bulletin, 2007, 105 (1), pp.147-152. hal-01453856

HAL Id: hal-01453856

https://hal.science/hal-01453856

Submitted on 31 May 2020

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

<figure><img src="image_2.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
# New information from fish diets on the importance of glassy flying squid (*Hyaloteuthis pelagica*) (Teuthoidea: Ommastrephidae) in the epipelagic cephalopod community of the tropical Atlantic Ocean

Yves Cherel (contact author)¹

Richard Sabatié²

Michel Potier³

Francis Marsac⁴

Frédéric Ménard⁴

¹ Centre d'Etudes Biologiques de Chizé
UPR 1934 du Centre National de la Recherche Scientifique BP 14
79360 Villiers-en-Bois, France
Email address for Y. Cherel: cherel@cebc.cnrs.fr

² Pôle Halieutique
Laboratoire d'Ecologie Halieutique, Agrocampus-Rennes
65 rue de Saint Brieuc
35042 Rennes Cedex, France

³ Institut de Recherche pour le Développement
Centre de La Réunion
UR 109 Thetis, BP 172
97492 Sainte Clotilde Cedex, Isle de La Réunion, France

⁴ Institut de Recherche pour le Développement
Centre de Recherche Halieutique Méditerranéenne et Tropicale
UR 109 Thetis, BP 171
34203 Sète Cedex, France

a fairly large number of accumulated beaks—were found in the stomachs of large predatory fishes during research cruises in the central Atlantic Ocean in autumn 2000. In this note, we describe the importance of *H. pelagica* in fish diets, thus adding new information about the abundance and trophic role of a poorly known ommastrephid species.

## Materials and methods

Fieldwork was carried out in the central Atlantic Ocean during three cruises of the Japanese RV *Shoyo Maru* in October–December 2000 (Fig. 1). Cruise I took place in temperate waters of the north equatorial current (between 8–21°N and 42–29°W) and cruises II and III took place in tropical waters of the south equatorial divergence (between 2N–10°S and 13–26°W, and between 7–9°S and 9–24°W). Cruises were a part of the Bigeye Tuna Year Program (BETYP) that was undertaken under the auspices of the International Commission for the Conservation of Atlantic Tunas (ICCAT). The purpose of the cruises was to tag live tunas caught by longlines in order to investigate their migration pattern and behavior in relation to fish aggregating devices.

Fish were measured (eye-fork length for billfishes and fork length for other species) and dissected onboard. In the laboratory, each fish stomach was thawed, opened, and both accumulated (cephalopod beaks with no flesh attached) and fresh items were sorted. Fresh remains were divided into broad prey classes (fish, cephalopods, crustaceans, and others), and weighed to calculate their proportion by mass in the diet. Identification of cephalopod prey relied on the external morphological features of either intact specimens or beaks.

Squids of the family Ommastrephidae are a vital part of marine food webs and support major fisheries around the world. They are widely distributed in the open ocean, where they are among the most abundant in number and biomass of nektonic epipelagic organisms. In turn, seven of the 11 genera of this family (*Dosi-dicus*, *Illex*, *Martialia*, *Nototodarus*, *Ommastrephes*, *Sthenoteuthis*, and *Todarodes*) are heavily preyed upon by top marine predators, i.e., birds, mammals, and fish, and currently support fisheries in both neritic and oceanic waters (Roper and Sweeney, 1984; Rodhouse, 1997). Their commercial importance has made the large ommastrephids the target of many scientific investigations and their biology is consequently reasonably well-known (Nigmatullin et al., 2001; Zuyev et al., 2002; Bower and Ichii, 2005). In contrast, much less

information is available on the biology and ecological role of the smaller, unexploited species of ommastrephids (e.g., *Eucleoteuthis*, *Hyaloteuthis*, *Ornithoteuthis*, and *Todaropsis*).

*Hyaloteuthis pelagica* (Bosc, 1802), the glassy flying squid, is the smallest ommastrephid, reaching a maximum mantle length of 90 mm (Nesis, 1987). It appears to be an epipelagic species that is probably distributed in all tropical and subtropical oceans (Nesis and Nigmatullin, 1979; Wormuth, 1998). *Hyaloteuthis pelagica* is rarely captured, but was caught in large numbers during a cruise off Brazil, where it was the dominant ommastrephid captured in nets (Warneke-Cremer, 1986). Almost nothing is known about its trophic relationships, either as prey or predator (Nesis and Nigmatullin, 1979). Numerous remains of *H. pelagica*—from a few intact squids to

Manuscript submitted 2 March 2006 to the Scientific Editor's Office.

Manuscript approved for publication 24 May 2006 by the Scientific Editor.
Fish. Bull. 105:147–152 (2007).
(both lower and upper) were identified by reference to features given by Clarke (1986) and by comparison with material held in our own reference collection.

Well-preserved specimens of *H. pelagica* were identified from the special arrangement of luminous spots on the ventral side of the mantle (Nesis, 1987). Beaks from those specimens identified from the spots (reference beaks) allowed us to identify almost all ommastrephid beaks found in fish samples as belonging to *H. pelagica*. Importantly, wings of the lower beaks darkened at a small size, thus precluding misidentification with beaks of other ommastrephid species that darken at larger sizes, e.g., *Sthenoteuthis pteropus* (Clarke, 1986). Lower rostral length (LRL) of beaks was measured to 0.1 mm with a vernier caliper and the allometric equations given by Clarke (1986) were used to estimate dorsal mantle length (ML) and whole wet mass (M) from LRL. Specimens of *H. pe-

lagica* were assumed to be adults at 46 mm ML and larger (Dunning and Brandt, 1985).

Dietary data are presented by using two calculation techniques, namely the frequency of occurrence and the percentage by number of each prey type. Data were statistically analyzed by using SYSTAT 9 (SPSS, Chicago, IL). Values given are means (±SD).

## Results

Most (97%) of the fish caught on longlines belonged to 10 different species of large oceanic predatory fishes, including longnose lancetfish (*Alepisaurus ferox*), four scombrids (wahoo [*Acanthocybium solandri*], albacore [*Thunnus alalunga*], yellowfin tuna [*T. albacares*], and bigeye tuna [*T. obesus*]), swordfish (*Xiphias gladius*), and four istiophorids (sailfish [*Istiophorus albicans*], blue marlin [*Makaira nigricans*], and white marlin [*Tet-rapturus albidus*], and longbill spearfish [*T. pfluegeri*]). Most of the fish (93%) contained fresh remains in their stomachs. Fish prey dominated the diet by mass (>50%) of eight predator species (Table 1). Fish and cephalopod items were almost equally important in the diet of white marlin, whereas fish, cephalopods, and crustaceans were the main food sources of albacore.

Cephalopods amounted to slightly more than 50% of the diet by mass in one fish species (white marlin) only. They were an important prey class (>10%) in five other species and were still a minor, but significant (≥5–10%), portion of the food of the four remaining fishes (Table 1). Overall, cephalopods (both fresh and accumulated items) were found in most of the individuals (76%) and a total of 2701 cephalopod beaks were identified from the stomach of 105 fish. *Hyaloteuthis pelagica* was by far the most important cephalopod prey of the community of large predatory fishes, amounting

to more than 50% of the total number of cephalopods (up to 93%) in six species (Table 2). Indeed, it was found to be the main cephalopod prey in all the fishes, except in bigeye tuna and lancetfish where it ranked second and third, respectively. *Hyaloteuthis pelagica* was much more abundant in the diet of fish caught in tropical waters (cruises II and III) than in the diet of individuals fished in temperate waters (cruise I) (n=1937 and 15 beaks, respectively).

Other important cephalopod prey (>10% by number) included the small onychoteuthid squid *Walvisteuthis* (= *Onykia*) *rancureli* in the diets of bigeye tuna and albacore, and the pelagic octopuses *Japetella diaphana* and common blanket octopus *Tremoctopus violaceus* in those of yellowfin and bigeye tunas, respectively. Three other ommastrephid squids were identified from fish stomach contents; they were two rare prey species, the Atlantic bird squid *Ornithoteuthis antillarum* and the orangeback flying squid *Sthenoteuthis pteropus*, as well as the bait, Argentine shortfin squid *Illex argentinus*.

All fishes fed upon the same size range of *H. pe-lagica*, including both juvenile and adult squids (Ta-ble 3, Fig. 2), but overall they segregated by prey-ing on squids of different sizes (ANOVA on LRL, F(6,907)=16.36, P<0.0001). *Post hoc* Tukey multiple comparison tests showed three groups of predators: yellowfin tuna and sailfish fed on smaller squids (51 mm and 3.9 g on average), bigeye tuna, white marlin, and longbill spearfish fed on larger individuals (60, 59, and 58 mm; 6.6, 6.2, and 5.7 g, respectively), and albacore and blue marlin fed on squids of intermedi-ate sizes (54 mm and 4.7–4.8 g). Accordingly, bigeye tuna, white marlin, and longbill spearfish fed more on adult squids (89%, 92%, and 93% of the total number of *H. pelagica*, respectively) than did albacore and blue marlin (85% and 77%) and yellowfin tuna and sailfish (62% and 73%) (Table 3).

<figure><img src="image_3.png" /><figcaption>Figure 1</figcaption></figure>

Locations of longline sets carried out in the central Atlantic Ocean during three cruises of the RV *Shoyo Maru* between October and December 2000.
<caption>**Table 1**</caption>

Frequency of occurrence (FO) and proportion by mass (%) of four broad prey classes (fish, cephalopods, crustaceans, and others) recovered from the stomach contents of 10 species of predatory fishes sampled between October and December 2000 in the central Atlantic Ocean.

<table><caption>**Table 2**</caption><thead><tr><th rowspan="2">Species</th><th rowspan="2">No. of specimens</th><th rowspan="2">Length ±SD (cm)</th><th rowspan="2">No. of stomachs with fresh remains</th><th colspan="2">Fish</th><th colspan="2">Cephalopods</th><th colspan="2">Crustaceans</th><th colspan="2">Others</th></tr><tr><th>FO</th><th>Mass</th><th>FO</th><th>Mass</th><th>FO</th><th>Mass</th><th>FO</th><th>Mass</th></tr></thead><tbody><tr><td><strong>Alepisauridae</strong></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td><em>Alepisaurus ferox</em></td><td>29</td><td>120 ±15</td><td>26</td><td>18</td><td>67.8</td><td>9</td><td>9.8</td><td>19</td><td>13.6</td><td>9</td><td>8.8</td></tr><tr><td><strong>Scombridae</strong></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td><em>Acanthocybium solandri</em></td><td>7</td><td>136 ±18</td><td>7</td><td>6</td><td>63.5</td><td>2</td><td>7.5</td><td>0</td><td>0.0</td><td>6</td><td>29.0</td></tr><tr><td><em>Thunnus alalunga</em></td><td>16</td><td>109 ±6</td><td>15</td><td>11</td><td>31.5</td><td>9</td><td>31.7</td><td>15</td><td>29.7</td><td>5</td><td>7.1</td></tr><tr><td><em>Thunnus albacares</em></td><td>6</td><td>147 ±7</td><td>6</td><td>6</td><td>77.2</td><td>5</td><td>5.8</td><td>5</td><td>12.1</td><td>2</td><td>4.9</td></tr><tr><td><em>Thunnus obesus</em></td><td>24</td><td>107 ±22</td><td>24</td><td>24</td><td>77.0</td><td>17</td><td>20.2</td><td>13</td><td>2.7</td><td>2</td><td>0.1</td></tr><tr><td><strong>Xiphiidae</strong></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td><em>Xiphias gladius</em></td><td>8</td><td>126 ±32</td><td>6</td><td>6</td><td>89.3</td><td>3</td><td>10.3</td><td>2</td><td>0.4</td><td>0</td><td>0.0</td></tr><tr><td><strong>Isiophoridae</strong></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td><em>Istiophorus albicans</em></td><td>4</td><td>152 ±13</td><td>4</td><td>3</td><td>85.7</td><td>4</td><td>13.1</td><td>0</td><td>0.0</td><td>1</td><td>1.2</td></tr><tr><td><em>Makaira nigricans</em></td><td>8</td><td>180 ±25</td><td>5</td><td>3</td><td>95.2</td><td>2</td><td>4.7</td><td>0</td><td>0.0</td><td>3</td><td>0.2</td></tr><tr><td><em>Tetrapturus albidus</em></td><td>7</td><td>130 ±10</td><td>7</td><td>7</td><td>48.2</td><td>6</td><td>51.2</td><td>0</td><td>0.0</td><td>4</td><td>0.6</td></tr><tr><td><em>Tetrapturus pfluegeri</em></td><td>30</td><td>143 ±6</td><td>29</td><td>25</td><td>86.8</td><td>23</td><td>13.0</td><td>4</td><td>0.0</td><td>4</td><td>0.1</td></tr></tbody></table>

Number (and % composition by number) of the main cephalopod prey species found in the diet of Scombridae and Istiophoridae from the tropical Atlantic Ocean between October and December 2000. Only prey species contributing more than 5% by number are reported. n = number of stomachs examined.

<table><thead><tr><th>Species</th><th>Thunnus alalunga n=15</th><th>Thunnus albacares n=5</th><th>Thunnus obesus n=19</th><th>Istiophorus albicans n=4</th><th>Makaira nigricans n=5</th><th>Tetrapturus albidus n=7</th><th>Tetrapturus pfluegeri n=29</th></tr></thead><tbody><tr><td><strong>Ommastrephidae</strong></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td><em>Hyaloteuthis pelagica</em></td><td>194 (51.5)</td><td>133 (61.6)</td><td>45 (19.8)</td><td>78 (80.4)</td><td>101 (75.4)</td><td>481 (92.9)</td><td>897 (85.8)</td></tr><tr><td><strong>Onychoteuthidae</strong></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td><em>Onychoteuthis banksi</em></td><td>21 (5.6)</td><td>4 (1.9)</td><td>2 (0.9)</td><td>0 (0.0)</td><td>2 (1.5)</td><td>1 (0.2)</td><td>12 (1.1)</td></tr><tr><td><em>Walvisteuthis rancureli</em></td><td>63 (16.7)</td><td>5 (2.3)</td><td>62 (27.3)</td><td>1 (1.0)</td><td>9 (6.7)</td><td>0 (0.0)</td><td>7 (0.7)</td></tr><tr><td><strong>Grimalditeuthidae</strong></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td><em>Grimalditeuthis bonplandi</em></td><td>4 (1.1)</td><td>2 (0.9)</td><td>17 (7.5)</td><td>0 (0.0)</td><td>0 (0.0)</td><td>2 (0.4)</td><td>0 (0.0)</td></tr><tr><td><strong>Tremoctopodidae</strong></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td><em>Tremoctopus violaceus</em></td><td>3 (0.8)</td><td>35 (16.2)</td><td>3 (1.3)</td><td>8 (8.2)</td><td>7 (5.2)</td><td>11 (2.1)</td><td>19 (1.8)</td></tr><tr><td><strong>Argonautidae</strong></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td><em>Argonauta argo</em></td><td>6 (1.6)</td><td>15 (6.9)</td><td>2 (0.9)</td><td>8 (8.2)</td><td>4 (3.0)</td><td>21 (4.1)</td><td>82 (7.8)</td></tr><tr><td><strong>Bolitaneidae</strong></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td><em>Japetella diaphana</em></td><td>34 (9.0)</td><td>5 (2.3)</td><td>28 (12.3)</td><td>0 (0.0)</td><td>1 (0.7)</td><td>0 (0.0)</td><td>7 (0.7)</td></tr><tr><td>Other cephalopods</td><td>52 (13.8)</td><td>17 (7.9)</td><td>68 (30.0)</td><td>2 (2.1)</td><td>10 (7.5)</td><td>2 (0.4)</td><td>21 (2.0)</td></tr><tr><td><strong>Total</strong></td><td>377 (100.0)</td><td>216 (100.0)</td><td>227 (100.0)</td><td>97 (100.0)</td><td>134 (100.0)</td><td>518 (100.0)</td><td>1045 (100.0)</td></tr></tbody></table>

Discussion

This study is the first, to our knowledge, to point out the abundance of *H. pelagica* in the tropical pelagic ecosystem. In the central Atlantic Ocean, *H. pelagica*

was found as a prey of all the fish species that were investigated. When looking at both the proportion by mass of cephalopods in the fish diet (Table 1) and the proportion by number of *H. pelagica* in their cephalopod diet (Table 2), *H. pelagica* was a major prey of white
<figure><img src="image_4.png" /><figcaption>Figure 2</figcaption></figure>

Frequency distribution of lower rostral lengths (LRL) (mm) of *Hyaloteuthis pelagica* glassy flying squid eaten by yellowfin tuna (*Thunnus albacares*), albacore (*Thunnus alalunga*), white marlin (*Tetrapturus albidus*), and longbill spearfish (*Tetrapturus pfluegeri*) in the tropical Atlantic Ocean.

<caption>Table 3</caption>

Characteristics of *Hyaloteuthis pelagica* eaten by large predatory fish from the tropical Atlantic Ocean. Values given are means (±SD) with ranges in parentheses. LRL=lower rostral length, ML=mantle length, M=body mass.

<table><thead><tr><th>Species</th><th>Number<br>(n)</th><th>Measured<br>LRL<br>(mm)</th><th>Estimated<br>ML<br>(mm)</th><th>Estimated<br>M<br>(g)</th><th>Adults<br>(ML >46 mm)<br>(%)</th></tr></thead><tbody><tr><td><strong>Alepisauridae</strong></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td><em>Alepisaurus ferox</em></td><td>2</td><td>1.6–1.8</td><td>60–64</td><td>6.1–7.3</td><td>100.0</td></tr><tr><td><strong>Scombridae</strong></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td><em>Acanthocybium solandri</em></td><td>3</td><td>2.1 ±0.2 (1.9–2.3)</td><td>71 ±5 (67–77)</td><td>9.7 ±2.0 (8.5–12.0)</td><td>100.0</td></tr><tr><td><em>Thunnus alalunga</em></td><td>95</td><td>1.4 ±0.3 (0.5–2.5)</td><td>54 ±8 (34–81)</td><td>4.7 ±2.1 (0.8–14.0)</td><td>85.2</td></tr><tr><td><em>Thunnus albacares</em></td><td>60</td><td>1.2 ±0.3 (0.8–1.9)</td><td>51 ±7 (39–67)</td><td>3.9 ±1.8 (1.5–8.5)</td><td>61.7</td></tr><tr><td><em>Thunnus obesus</em></td><td>18</td><td>1.6 ±0.5 (0.8–2.3)</td><td>60 ±11 (39–77)</td><td>6.6 ±3.2 (1.5–12.0)</td><td>88.9</td></tr><tr><td><strong>Xiphiidae</strong></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td><em>Xiphias gladius</em></td><td>5</td><td>1.9 ±0.2 (1.6–2.2)</td><td>67 ±6 (59–75)</td><td>8.4 ±2.0 (5.9–11.3)</td><td>100.0</td></tr><tr><td><strong>Istiophoridae</strong></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td><em>Istiophorus albicans</em></td><td>33</td><td>1.3 ±0.2 (0.9–1.8)</td><td>51 ±5 (42–64)</td><td>3.9 ±1.3 (2.0–7.3)</td><td>72.7</td></tr><tr><td><em>Makaira nigricans</em></td><td>39</td><td>1.4 ±0.4 (0.5–2.0)</td><td>54 ±9 (34–69)</td><td>4.8 ±2.2 (0.8–9.2)</td><td>76.9</td></tr><tr><td><em>Tetrapturus albidus</em></td><td>239</td><td>1.6 ±0.3 (0.7–2.3)</td><td>59 ±8 (38–78)</td><td>6.2 ±2.4 (1.4–12.4)</td><td>92.1</td></tr><tr><td><em>Tetrapturus pfluegeri</em></td><td>430</td><td>1.5 ±0.3 (0.7–2.4)</td><td>58 ±8 (37–79)</td><td>5.7 ±2.2 (1.2–12.8)</td><td>92.6</td></tr></tbody></table>

marlin, a common food item of albacore, longbill spear-fish, and sailfish and a minor prey for the remaining fishes. However, more information is needed to assess the spatiotemporal importance of *H. pelagica* in the

fish community, because 1) all fish were caught during a relatively short period of time, and 2) a medium to low number of specimens per fish species were collected during the cruises.
The ommastrephid *Sthenoteuthis pteropus*, usually
abundant in the tropical Atlantic Ocean, was surpris-
ingly absent in fish diets in the present study. Two
hypotheses may account for that apparent absence:
either fish selected *H. pelagica* rather than *S. pteropus*,
or *S. pteropus* was not an important and available nek-
tonic prey organism at the time of sampling. The latter
hypothesis is likely to be the best explanation because
tunas and billfishes are known to be opportunistic
predators. Moreover, the geographical distribution of *S.
pteropus* shows that juvenile squids are not abundant in
the central Atlantic Ocean where cruises of the present
investigation took place (Warneke-Cremer, 1986; Zuev
and Nikolsky, 1993). Instead, our study underlines the
numerical importance of *H. pelagica*, together with *O.
antillarum* (Vaske et al., 2004), in the area, and our
numbers are in agreement with the large catches of
the species with nets between 20°S and 31°S off Brazil
during 1966 and 1968 (Warneke-Cremer, 1986).

The present study documents the largest number
of *H. pelagica* ever reported, thus emphasizing the
usefulness of marine predators to gain valuable in-
formation on the biology of their prey (Clarke, 1980;
Cherel et al., 2004). Other ommastrephid species are
important food items of various fishes, seabirds, and
marine mammals (Clarke, 1996; Cherel and Klages,
1998), but *H. pelagica* was previously found only as
a rare prey of squids (Shchetinnikov, 1992), fishes
(Matthews et al., 1977; Okutani and Tsukada, 1988;
Vaske et al., 2004), birds (Harrison et al., 1983), and
cetaceans (Robertson and Chivers, 1997). In the same
way, the squid *Grimalditeuthis bonplandi* and the pe-
lagic octopods *T. violaceus* and *J. diaphana* were rarely
found in significant numbers in the diet of cephalopod
predators (Okutani and Tsukada, 1988; Le Corre et
al., 2003), but we commonly found them as fish prey.
Consequently, our study shows that these poorly known
cephalopods, together with adults of *H. pelagica*, con-
stitute a link in the transfer of energy from lower
trophic levels (most likely mesozooplankton) to higher
trophic levels (including tunas and billfishes) in the
tropical Atlantic Ocean).

Acknowledgments

The authors thank P. Borsa, P. Dewals, and O. Maury
for their help to collect scientific samples on board, and
the captain and crew of the RV *Shoyo-Maru*.

Literature cited

Bower, J. R., and T. Ichii.

2005. The red flying squid (*Ommastrephes bartramii*): a review of recent research and the fishery in Japan. Fish. Res. 76:39-55.

Cherel, Y., G. Duhamel, and N. Gasco.

2004. Cephalopod fauna of subantarctic islands: new information from predators. Mar. Ecol. Prog. Ser. 266:143-156.

Cherel., Y., and N. Klages.

1998. A review of the food of albatrosses. *In* Albatross biology and conservation (G. Robertson, and R. Gales, eds.), p 113–136. Surrey Beatty and Sons, Chipping Norton, Australia.

Clarke, M. R.

1980. Cephalopoda in the diet of sperm whales of the Southern Hemisphere and their bearing on sperm whale biology. Discovery Rep. 37:1-324.

1986. A handbook for the identification of cephalopod beaks, 273 p. Clarendon Press, Oxford, England.

1996. The role of cephalopods in the world's oceans. Phil. Trans. R. Soc. Lond. B 351:977-1112.

Dunning, M., and S. B. Brandt.

1985. Distribution and life history of deep-water squid of commercial interest from Australia. Aust. J. Mar. Freshw. Res. 36:343-359.

Harrison, C. S., T. S. Hida, and M. P. Seki.

1983. Hawaiian seabird ecology. Wildl. Monogr. 85: 1-71.

Le Corre, M., Y. Cherel, F. Lagarde, H. Lormée, and P. Jouventin.

2003. Seasonal and interannual variation in the feed-
ing ecology of a tropical oceanic seabird, the red-tailed
tropicbird *Phaethon rubricauda*. Mar. Ecol. Prog. Ser.
255:289-301.

Matthews, F. D., D. M. Damkaer, L. W. Knapp, and B. B. Collette.

1977. Food of western North Atlantic tunas (*Thunnus*) and lancetfishes (*Alepisaurus*). NOAA Tech. Rep. NMSF SSRF-706, 19 p.

Nesis, K. N.

1987. Cephalopods of the world. Squids, cuttlefishes, octopuses, and allies, 351 p. TFH Publs., Neptune City, NJ.

Nesis, K. N., and C. M. Nigmatullin.

1979. The distribution and biology of the genus *Orni-
thoteuthis* Okada, 1927 and *Hyaloteuthis* Gray, 1849
(Cephalopoda: Oegopsida). Bull. Moscow Soc. Nat.
84:50-63. [In Russian.]

Nigmatullin, C. M., K. N. Nesis, and A. I. Arkhipkin.

2001. A review of the biology of the jumbo squid *Dosidi-
cus gigas* (Cephalopoda:Ommastrephidae). Fish. Res.
54:9-19.

Okutani, T., and S. Tsukada.

1988. Squids eaten by lancetfish and tunas in the tropical Indo-Pacific Ocean. J. Tokyo Univ. Fish. 75:1-44.

Robertson, K. M., and S. J. Chivers.

1997. Prey occurrence in pantropical spotted dol-
phins, *Stenella attenuata*, from the eastern tropical
Pacific. Fish. Bull. 95:334-348.

Rodhouse, P. G.

1997. Large and meso-scale distribution of the ommas-
trephid squid *Martialia hyadesi* in the Southern Ocean: a synthesis of information relevant to fishery forecasting and management. Korean J. Polar Res. 8:145-154.

Roper, F. E., and M. J. Sweeney.

1984 Cephalopods of the world. An annotated and illus-
trated catalogue of species of interest to fisheries. FAO
Species Catalogue 3:1-277.

Shchetinnikov, A. S.

1992. Feeding spectrum of squid *Sthenoteuthis oualaniensis* (Oegopsida) in the eastern Pacific. J. Mar. Biol. Assoc. U.K. 72:849-860.

Vaske Jr., T., C. M. Vooren, and R. P. Lessa.

2004. Feeding habits of four species of Istiophoridae (Pisces: Perciformes) from northeastern Brazil. Environ. Biol. Fishes 70:293-304.
Warneke-Cremer, C.

1986. Contributions to the systematics of ommastrephid squid (Mollusca, Cephalopoda, Teuthoidea) and their distribution in the Atlantic, based on the catches of FFS "Walter Herwig" made during 1966 and 1968. Mitteil. Inst. Seefisch. Hamburg 40:1-116. [In German.]

Wormuth, J. H.

1998. Workshop deliberations on the Ommastrephidae: a brief history of their systematics and a review of the systematics, distribution, and biology of the Genera *Martialia* Rochebrune and Mabille, 1889, *Todaropsis* Girard, 1890, *Dosidicus* Steenstrup, 1857, *Hyaloteuthis* Gray, 1849, and *Eucleoteuthis* Berry, 1916. *Smithsonian Contrib. Zool.* 586:373-383.

Zuev, G. V., and V. N. Nikolsky.

1993. Ecological mechanisms related to intraspecific structure of the nektonic squid *Sthenoteuthis pteropus* (Steenstrup). In *Recent advances in fisheries biology* (T. Okutani, R. K. O'Dor, and T. Kubodera, eds.), p. 653-664. Tokai Univ. Press, Tokyo, Japan.

Zuyev, G., Ch. Nigmatullin, M. Chesalin, and K. Nesis.

2002. Main results of long-term worldwide studies on tropical nektonic oceanic squid genus *Sthenoteuthis*: an overview of the Soviet investigations. Bull. Mar. Sci. 71:1019-1060.