Pelagic Longline Catch Composition Image:

Introduction Data Collection Duties 1. Estimate effort for each gear deployment; 2. Identify every individual caught and assess catch condition and fate; 3. Collect biological information on target and other identified species as requested; 4. Record all sightings and interactions with marine mammals and sea turtles; 5. Record vessel and fishing gear characteristics.

Objectives  Describe the catch composition sampling process for pelagic longlining  Describe 2 situations when you can modify the standard catch composition sample  List 3 pieces of information that must be collected from every animal caught  List 3 types of gear needed on deck for catch composition sampling  Demonstrate ability to complete the Catch Composition form

Catch Composition form  1 per set  For each fish, record Species code (lowest taxonomic level) Condition Kept/return

Catch Composition Form

Hook number assigned based on direction of gear deployment Deployment Direction

Catch Composition Form

Damage – M arine mammal (usu. toothed whale)  often only head remains  Widely spaced tooth punctures  Often on multiple fish  Jagged bite edges Images: Chapman et al. 2006

Damage – C ookie cutter  circular / oval – clean edges Images: Chapman et al. 2006

Damage – other S hark  Large bites; few long strips of tissues  Gouge marks from individual teeth – look more like lacerations  Frequently multiple bites Images: Chapman et al. 2006

Catch Composition Form

Straight vs. Curved lengths 48 cm 53 cm

Curved vs straight lengths

Length Rule of Thumb (primary measurements)  Swordfish and billfish – lower jaw to fork length, curved (type 05C)  Tunas & most other fish – straight fork length (type 01S)  Sharks – stretched total length (type 13S) or fork length (type 01S)

Length Rule of Thumb (primary measurements)  Rays – total length (type 02S)  suborder Myliobatoidei - disc length to pelvic fin (type 14S)

Length Rule of Thumb (secondary measurements)  Swordfish and billfish –eye to fork length (type 04C) or Cleithrum to caudal keel (07C)  Tunas – pectoral fin to fork (09S)  Sharks & most other fish – straight fork length (type 01S)  Skates/Rays – disc width (11S)

Catch Composition Form

Catch composition – sampling exceptions IssueAlternative Too many fish to keep up Reduce number of sexed lengths Rough seas / seasickCease measurements but still try to watch Hunger / toiletSelect a random subsample

Catch Composition Form  Questions on catch composition sampling?  Practice exercise  Groups of 2  Same vessel, observer, tripID, set # used in Set & Haul Information Exercise  Number hooks 1 to 20

Activity - answers

Summary  Describe the catch composition sampling process for pelagic longlining  List 3 pieces of information that must be collected from every animal caught  when you can modify the standard catch composition sampling protocol and describe the modification for each

Summary  What sort of equipment do you think you will need for catch composition sampling on pelagic longline vessels? Foul weather gear Clip board & deck sheets Pencils Measuring tape Tally (thumb) counters

References  Brogan, D., S. Fukofuka, and P. Sharples Longline Observer Guide. Secretariat of the Pacific Community Oceanic Fisheries Programme, Noumea, New Caledonia.  Chapman, L., P. Sharples, D. Brogan, A. Desurmont, S. Beverly, and W. Sokimi Marine species identification manual for horizontal longline fishermen. Secretariat of the Pacific Community, New Caledonia.  NMFS. 2008a. American Samoa Observer Program Manual. Pacific Islands Regional Office, Sustainable Fisheries Division  PIRO Hawaii Longline Observer Program Observer Field Manual. Pacific Islands Regional Office, NMFS, Honolulu, HI.  Southeast Fisheries Science Center Pelagic Observer Program - Observer Manual. Pelagic Observer Program, Miami, FL.  SPC SPC/FFA Scientific Observer forms. Secretariat of the Pacific Community and Forum Fisheries Agency.

Homework #1

Lengths  Tuna – Fork length (straight)  Billfish – lower jaw to fork (curved)  Sharks Distinct fork – fork length (straight) Fork not distinct – stretched total length (straight)  Rays Myliobatoidei – disc length to pelvic fin All except above – total length

Lengths  Tunas  Billfish

Dusky Shark Carcharhinus obscurus Interdorsal ridge Free end of 2 nd dorsal < 2.5 times the height of the 2 nd dorsal fin Long pectoral fins, falcate toward rear margins Dorsal fin low and rounded on top Dorsal fin origin posterior to pectoral fin free margin Snout length equal to or shorter than mouth width 10

Nurse shark Ginglymostoma cirratum Barbels present Small beady eyes First dorsal fin origin above pelvic fin origin Lower lobe of caudal fin not well developed 26

Blueshark 1

Shortfin mako Isurus oxyrhincus White ventral surface Lunate caudal fin Pointed snout Single keel on each side of caudal peduncle Pectoral fins shorter than head length 1st dorsal fin origin posterior to pectoral fin free rear tip 2nd dorsal fin insertion anterior to anal fin origin 22

Bigeye thresher Alopias superciliosus Groove in head Extremely elongated caudal fin 1st dorsal fin free rear tip extends equal or posterior to pelvic fin origin Large upward looking eyes 1st dorsal fin insertion close proximity to pelvic fin origin 22

 Disc length (pelvic) –Tip of the snout to the posterior edge of the pelvic fins  Typical measurement for Myliobatoidei Measurement types - fish

 Disc width – distance between opposite wing tips  Secondary measurement for skates, rays

Damage – Squid  Jagged wound edges & surfaces  Sucker marks near wound edge & on body  backbone & vertebrae, if present, picked fairly clean  Anywhere on fishes body Images: Chapman et al. 2006

Damage – Birds  Jagged wound edges & surfaces  Many short strips of skin & muscle left in wound area  Many scratch marks from beak around wound edge & on body  Usually on softer body parts Images: Chapman et al. 2006