Investigations of Southern Ocean cephalopods began

with the pioneering expedition of HMS Challenger

(Hoyle,1886) and Valdivia expedition conducted by

Germany (Odhner, 1923). After the 1970s, there has been

considerable research effort in cephalopod taxonomy

and abundance all over the world. However, very little

is known about the abundance and biodiversity of

cephalopods in the Southern Ocean sector. Southern

Ocean cephalopod fauna is distinctive, with high levels

of endemism in the squid and play an important role,

linking the abundant mesopelagic fish and crustaceans

with higher predators such as albatross, seals and whales. Although not yet commercially exploited species of the family Ommastrephidae have high potential (Collins

and Rodhouse, 2006)

Mohamed, K S

Ragesh, N

Saji Kumar, K K

English

Sajikumar, K K

CMFRI Digital Repository

ICAR-CMFRI | Marine Fisheries Information Service Technical & Extension Series No. 243, 2020 7Renewed research focus on cephalopod resources in the Southern OceanK. K. Sajikumar*, N. Ragesh and K. S. MohamedICAR-Central Marine Fisheries Research Institute, Kochi-682 018, Kerala*E-mail: sajikumar.kk@icar.gov.inResearch CommunicationsIntroductionInvestigations of Southern Ocean cephalopods began with the pioneering expedition of HMS Challenger (Hoyle,1886) and Valdivia expedition conducted by Germany (Odhner, 1923). After the 1970s, there has been considerable research effort in cephalopod taxonomy and abundance all over the world. However, very little is known about the abundance and biodiversity of cephalopods in the Southern Ocean sector. Southern Ocean cephalopod fauna is distinctive, with high levels of endemism in the squid and play an important role, linking the abundant mesopelagic fish and crustaceans with higher predators such as albatross, seals and whales. Although not yet commercially exploited species of the family Ommastrephidae have high potential (Collins and Rodhouse, 2006). As a national policy objective (NPMF, 2017) India looks at commercial exploitation of marine resources in Areas Beyond National Jurisdiction (ABNJ), and therefore, it will be appropriate if the stock abundance and distribution of commercial cephalopod stocks are well understood. Besides, India is one among 25 member countries of the CCAMLR (Commission for the Conservation of Antarctic Marine Living Resources) aiming for the conservation of marine life in Antarctic Ocean. It is in the light of the above that the Molluscan Fisheries Division of ICAR-CMFRI proposed a study on the assessment of cephalopod biodiversity in the Southern Ocean with particular reference to commercial exploitable cephalopod stocks, including understanding the age and growth of Southern Ocean squids using statoliths and investigating their role as a predator from stomach content analysis. The proposal was approved by the National Centre for Polar and Ocean Research (NCPOR), Goa under the Ministry of Earth Sciences, Government of India and results of the study during the 10th and 11th Southern Ocean expeditions (SOE)are given below.Cruise transects and samplingA 111 m LOA, ice-strengthened training ship “MV Agulhas” from South Africa, was used for the expeditions (Table 1).AbstractResearchers from ICAR-CMFRI participated in 2 cruises to the Southern Ocean during 2017 and 2020 to gather information on cephalopod resources of the Antarctic region. Four species of squids including three species of ommastrephid squids such as Purpleback flying squid, Sthenoteuthis oualaniensis, Neon flying squid, Ommastrephes cylindraceus (Ommastrephes bartramii), Antarctic squid Todarodes filippovae and one cranchid squid, the Glass squid Galiteuthis glacialis were recorded. The presence of paralarvae and juveniles of ommastrephid squid in surface waters between 45°S to 46°S and 57° 29' E to 72°E indicates this area may be their spawning ground. The paralarvae of mesopelagic glass squids Galiteuthis glacialis collected from 66° to 57° S and 80° E to 57° E were aged by analysing their statoliths.Keywords: Southern Ocean, cephalopods, paralarvae, statolithsICAR-CMFRI | Marine Fisheries Information Service Technical & Extension Series No. 243, 2020 810th Indian SOESampling was carried out in the area between 39°56'S to 66°39'S latitude and 57°25'E to 76°24'E longitude as per the cruise track (Fig.1A). 28 observations including those from 7 squid jigging stations, 13 IKMT stations (21 operations) and 8 zooplankton sampling operations were made (Table 2 & Fig. 2).Ommastrephid squids including Neon flying squid Ommastrephes bartramii (Fig.3a), Antarctic flying squid Todarodes filippovae (Fig.3b) and Purpleback flying Table 1. Details of the SOE undertaken for research on molluscan resources in Southern OceanExpedition Vessel Period Number of participantsTypes of equipment carried by ICAR-CMFRI10th SOE MV Agulhas 08.12.2017 to02.03. 2018 (59 days) 35 Issacs-Kidd Midwater Trawl (IKMT), squid jigs, zooplankton net11th SOE MV Agulhas 06.01.2020 to 08.03.2020 (62 days)39 Automatic squid jigging machine, IKMT, Rectangular midwater trawl, squid jigsFig.1. The cruise track and stations for cephalopod observations during (A) 10th and (B) 11th Indian SOETable 2. Sampling stations and operations conducted during 10th Indian SOEDate Location Operation Depth of operation14/12/2017 40°11’S; 58°30’E Squid jigging 30 m18/12/2017 43°02’S; 60°36’E IKMT Surface, 200 m22/12/2017 54°00’S; 68°05’E Squid jigging 30 m23/12/2017 54°01’S; 60°07’E IKMT Surface, 200 m25/12/2017 58°55’S; 70°09’E Squid jigging 3027/12/2017 63°01’S; 70°05’E Zooplankton net Surface30/12/2017 65°31’S; 74°45’E Zooplankton net Surface31/12/2017 65°32’S; 72°50’E Zooplankton net Surface3/1/2018 66°33’S; 76°24’E Zooplankton net Surface4/1/2018 66°32’S; 76°24’E Zooplankton net Surface5/1/2018 66°37’S; 76°07’E Zooplankton net Surface6/1/2018 66°39’S; 76°06’E Zooplankton net SurfaceICAR-CMFRI | Marine Fisheries Information Service Technical & Extension Series No. 243, 2020 9Date Location Operation Depth of operation8/1/2018 65°28’S; 70°56’E IKMT Surface9/1/2018 65°31’S; 69°08’E IKMT 100 m10/1/2018 65°29’S; 66°58’E IKMT Surface, 500 m 11/1/2018 65°30’S; 64°56’E IKMT Surface, 500 m 12/1/2018 65°46’S; 62°48’E Zooplankton net Surface13/1/2018 65°27’S; 60°57’E IKMT Surface, 500 m 15/1/2018 65°27’S; 57°50’E IKMT 500 m21/1/2018 57°00’S; 57°36’E IKMT Surface, 500 m 24/1/2018 51°04’S; 57°25’E IKMT,squid  jigging Surface, 500 m25/1/2018 47°30’S; 57°29’E IKMT, squid jigging Surface, 500 m28/1/2018 40°11’S; 58°24’E IKMT, squid jigging Surface29/1/2018 39°56’S; 57°30’E IKMT, squid jigging 200 mFig. 2. Sampling operations during the 10th and 11th Indian expedition to Southern Ocean/ Antarctic waters (a) RMT (b) IKMT, for cephalopod paralarvae and juveniles; (c) Automatic squid jigging machine used for the capture of adult squids.acbICAR-CMFRI | Marine Fisheries Information Service Technical & Extension Series No. 243, 2020 10squid Sthenoteuthis oualaniensis and their abundance was observed in three stations, 47° S-57° E, 40° S-58° E and 39° S-57° E. Paralarvae of mesopelagic squids collected from 65° S 66° E to 57° S 57° E were identified as Galiteuthis glacialis (Fig. 3). Before the 10th SOE, the Neon flying squid, Ommastrephes bartramii was considered a monotypic cosmopolitan species with a discontinuous distribution. From the results of the 10th expedition, a combination of morphological and metabolic information were used to resurrect formerly synonymized name Ommastrephes cylindraceus (ie., Ommastrephes bartramii = Ommastrephes cylindraceus) and propose a revision in the distribution range in collaboration with other international cephalopod researchers (Fernandez-Alvarez et al., 2020). Additionally, the distribution, abundance and growth of the paralarvae and juveniles of the glass squid Galiteuthis glacialis which were collected from IKMT tows conducted at 500 m depth in Prydz Bay, Antarctica has been documented. Early life stages of G. glacialis were distributed over the shelf edge waters of Prydz Bay. Their abundance ranged from 1 to 9 individuals/1000 m3 with highest abundance observed in both 65° S; 70° E and 66° S; 76° E, which is 120 nautical miles (nmi) north of land area of Prydz Bay (Fig.4). The smallest paralarvae were observed in 65° S; 57° E and largest individuals recorded at 57° S; 57°37' E.A total of 53 early life stage individuals of Galiteuthis glacialis ranging in size from 6.3 to 28.4 mm DML were caught during the survey which included 42 paralarvae and 11 juveniles. The pair of statocysts acebdfFig. 3. Squids collected during 10th and 11th expeditions. (a) Ommastrephes cylindraceus, (b)Todarodes filippovae, (c)Sthenoteuthis oualaniensis, (d) Live Galiteuthis glacialis, (e) Galiteuthis glacialis, (f) Unidentified ommastrephid juvenileICAR-CMFRI | Marine Fisheries Information Service Technical & Extension Series No. 243, 2020 11Fig. 4. Distribution and abundance of paralarvae and early juveniles of Galiteuthis glacialis in the Indian sector of Southern Ocean (near Prydz Bay). Circles = relative abundanceTable 3. Hydrographic characteristics of Mola mola sighting site.Characteristics VariablesAtmospheric temperature (AT) 12.5°CSea surface temperature (SST) 16.0°CHumidity 90%Wind speed 14 mphWater depth 3475 mlocated in the ventral posterior region of the head had growth rings that ranged from 47 to 106 (6.3 to 28.4 mm DML) (Fig. 5). Age of individuals estimated based on statolith increment counts ranged from 47 to 85 days with a daily growth rate ranging from 0.13 to 0.25 mm dorsal mantle length (DML)/day (mean 0.18 mm) for paralarvae. The early juveniles had an age of 85 to 103 days with a slightly faster growth rate ranging from 0.21 to 0.27 mm DML/day (mean 0.24 mm). The presence of paralarve of G. glacialis at the outer continental shelf edge of Prydz Bay during austral summer indicates a probable spawning site in this area (Sajikumar et al., 2020). Other observations during the cruise in the Southern Indian Ocean included an opportunistic sighting (39° 59' 49"; 57° 30' 50") of a single sunfish Mola mola on 15th December 2017 (Fig. 6).The hydrographic characteristics such as atmospheric temperature (AT), Sea Surface Temperature (SST), humidity and wind speed at the site where the sunfish was sighted are given in Table 3.11th Indian SOEThe sampling was carried out in the area between 39°16' to 67°00' S latitude and 57°28' to 80°04' E longitude (Fig. 1B and Table.4). At each station, sampling for early stages of cephalopods was done using Rectangular midwater trawl (Fig. 2A) and Issacs-Kidd Midwater Trawl (IKMT) (Fig. 2B) operated below the surface and 500 m. Both vertical and horizontal hauls were made. The squids were caught in the night hours after attracting them using LED lamps (4 x 500 watts) by using hand ICAR-CMFRI | Marine Fisheries Information Service Technical & Extension Series No. 243, 2020 12Fig. 5. (a) Dorsal view of G. glacialis (11 mm DML), (b) light micrograph of statocyst (arrow indicates the position of statolith), (c) light micrograph of statolith of G. glacialis (16 mm DML)Fig.6. Ocean sunfish Mola mola sighteda cb5 mm100 µmICAR-CMFRI | Marine Fisheries Information Service Technical & Extension Series No. 243, 2020 13Table 4. Sampling stations and operations carried out during the 11th Indian SOEDate Location Operation Depth of operation 29/01/2020 45° 00 S;72°00 E IKMT, squid jigging Surface, 500 m04/02/2020 65° 00 S;80°04 E IKMT Surface, 500 m07/02/2020 67° 00 S;80°00 E RMT 300 m08/02/2020 67° 32 S;76°50 E RMT 250 m09/02/2020 65° 00 S;76°59 E IKMT Surface, 500 m10/02/2020 65° 00 S;73°59 E IKMT Surface, 500 m11/02/2020 67° 00S; 74°00 E IKMT 500 m 12/02/2020 66° 50S; 71°00 E RMT 300 m15/02/2020 66° 56S; 67°58 E IKMT 500 m16/02/2020 67° 00S; 64°50 E IKMT 500 m18/02/2020 65° 00S; 62°02 E IKMT 500 m19/02/2020 66° 52S; 61°57 E IKMT 200 m20/02/2020 65° 31S; 57°29 E RMT 1000 m22/02/2020 61° 59S; 57°28 E IKMT 500 m24/02/2020 60° 00S; 57°30 E IKMT Surface, 500 m 25/02/2020 57° 00S; 57°29 E IKMT, squid jigging Surface, 500 m 28/02/2020 50° 24S; 57°29 E IKMT, squid jigging Surface29/02/2020 46° 59S; 57°29 E IKMT, squid jigging Surface, 500 m 02/03/2020 43° 00S; 57°30 E IKMT, squid jigging Surface03/03/2020 39° 16S; 57°28 E Squid jigging Surface jigs and automatic squid jigging machine (Hamade MY- 3DP) with centralized control panel (Fig. 2C). However, jigging operations could be carried out only rarely on most of the nights due to very rough seas, strong currents and winds during the expedition. Abundance estimation of ommastrephid squids were undertaken in all stations by visual observation method (Chesalin and Zuyev, 2002).Three species of cephalopods Ommastrephes bartramii (O.cylindraceus), Todarodes filippovae and Sthenoteuthis oualaniensis were collected using automatic squid jigging machine and hand jig while Galiteuthis glacialis was collected using IKMT. The pelagic neon flying squid Ommastrephes bartramii (Ommastrephes cylindraceus) was observed at 39°16' S; 57°28' E. Paralarvae and juveniles of ommastrephid squids were observed in surface waters of 45°00' S; 72°00' E and juveniles were observed at 46° 59' S; 57°29' E and 43°00' S; 57°30' E. Paralarvae of mesopelagic squids collected from 66° to 57° S and 80° E to 57° E were identified as Galiteuthis glacialis. The IKMT collected paralarvae of G.glacialis of 13 mm DML could be successfully maintained onboard in a glass tank up to 4 hours Fig.3d.During the expedition 25 stations were covered among which 6 were squid jigging stations, 15 IKMT stations (23 operations) and 4 stations for RMT operations. Antarctic Krill Euphausia superba was also collected using IKMT from 500 m depth from 45°S to 60°S latitude along the cruise track and these are being analysed.Seabirds, fish, penguin and seals of the Southern Indian Ocean were recorded during the expeditions. Nine species of seabirds were identified during the expedition (Table 5 and Fig.7). The southern giant petrel Macronectes giganteus was the most common species in the Southern Ocean. Several groups of Adelie penguin Pygoscelis adeliae Antarctic seals such as crabeater seal Lobodon carcinophagus and leopard seal Hydrurga leptonyx were observed near Prydz Bay (Fig.8).ICAR-CMFRI | Marine Fisheries Information Service Technical & Extension Series No. 243, 2020 14adgbehcfiFig.7. Seabirds observed during the 10th and 11 th Indian Expedition to Southern Ocean/Antarctic waters. (a) Thalassoica antarctica,(b) Diomedea exulans (c)Macronectes giganteus, (d) Daption capense, (e) unidentified, (f) Fulmarus glacialoides, (g) Diomedea sanfordi, (h) Procellaria aequinoctialis, (i) Diomedea epomophoraTable 5. List of birds observed during the  10th and 11th Indian SOESpecies Common name Position IUCN statusDiomedea epomophora Southern royal albatross 61° 48’ S;57°14’ E VulnerableProcellaria aequinoctialis White-chinned petrel 40°12’S to 62°35’S VulnerableDiomedea sanfordi Northern royal albatross 60° 23’S;57°30’E EndangeredFulmarus glacialoides  Southern fulmar 65° 20’S;63°12’E Least concernUnidentified - 66° 56’S;67°58’ E -Daption capense Cape petrel 66° 50’S;71°00’ E Least concernMacronectes giganteus Southern giant petrel 57° 00’S to 67°00’S Least concernDiomedea exulans Wandering albatross 61° 00’S;57°28’ E VulnerableThalassoica antarctica Antarctic petrel 56°28’S;57°29 E Least concernICAR-CMFRI | Marine Fisheries Information Service Technical & Extension Series No. 243, 2020 15EndnoteThese expeditions suggest the fishery potential of squids belonging to family ommastriphidae, such as Ommastrephes cylindraceus and Todarodes filippovae distributed up to 45°S during austral summer. The distribution of Sthenoteuthis oualaniensis is restricted up to 40°S. The occurrence of the paralarvae and juveniles indicate that Austral summer may be the spawning season for these species in the Southern Indian Ocean. Further on-board/in situ statolith increment validation studies for confirming the periodicity of statolith increment formation of Antarctic squids is needed. It is also necessary to carry out more night observations (squid jigging and abundance estimation) especially in the frontal region of the Southern Ocean (40°S) for a comprehensive understanding the abundance and distribution of these valuable resources of the Antarctic. There is also need to understand the relationship between squid stock size, recruitment variability and oceanographic systems.Fig.8. Crabeater seal of Southern OceanAcknowledgementsThe authors are grateful to the Director, ICAR-Central Marine Fisheries Research Institute, Kochi, India, and Dr. Anil Kumar N, Head, Ocean Science Department, National Centre for Polar and Ocean Research (NCPOR), Goa for the encouragement and support during the study.ReferencesChesalin, M. V and Zuyev, G. 2002. Bull. Mar. Sci., 71: 209–221.Clarke M. R. 1996. Philos. T. R. Soc. 351:977–1112.Collins, M. A., and Rodhouse, P. G. K.2006. Adv. Mar. Bio., 50: 191–265.Fernández-Alvarez, A. F et al., 2020. Zool. J. Linn. Soc-Lond. https://doi.org/10.1093/zoolinnean/zlaa014Hoyle,W. E. 1886. Zoology 16:1-246.National Policy of Marine Fisheries (NPMF) 2017. Ministry of Agriculture and Farmers Welfare.Odhner, T. 1923. Zoologisk Avdelning 27:1-39.Rodhouse, P. G (2005). FAO Fisheries Technical Paper,457:175-187.Sajikumar, K. K et al., 2020. Deep Sea Res. Part II https://doi.org/10.1016/j.dsr2.2020.104783.

Renewed research focus on cephalopod

resources in the Southern Ocean

http://eprints.cmfri.org.in/14666/1/MFIS_243_K%20K%20Sajikumar_2020.pdf

Renewed research focus on cephalopod resources in the Southern Ocean

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