General Fisheries Commission for the Mediterranean
Scientific Advisory Committee
sub-committee
on
environment and marine ecosystems
Third meeting
Barcelona the 4-9th of May 2002
MEDLEM PROGRAM
Mediterranean Large Elasmobranchs Monitoring
Subproject Basking shark
IMEDEA
MEDLEM PROGRAM
(Mediterranean Large Elasmobranchs Monitoring)
Subproject Basking shark
The Basking shark (Cetorhinusmaximus) is not a target of any Mediterranean fisheries while this happened in other colder marine regions, where this species has been widely exploited for a long time (U. K., Western Ireland and Norway). In addition to the few sightings made in the open sea, the presence of this shark is mainly evidenced by incidental catches in the trammel nets or in other artisanal fisheries which are frequently used along coastal waters of Mediterranean countries. The Basking shark is the largest Elasmobranch in the Mediterranean Sea and with the giant devilray (Mobula mobular) are the only filter feeders among the cartilaginous fish living in the region. The presence of this species in the Mediterranean region (especially in the north-western part) can be considered frequent mainly in spring and early summer, while sightings during the winter period are rare (Serena et al., 1999).
The Basking shark is probably one of the species that most requires measures of protection, considering its reproductive strategy. In fact it has been included in the Annex II (Endangered or Threatened Species) of the Barcelona Convention for the Protection of the Mediterranean Sea (1976), in the Protocol Concerning Specially Protected Areas and Biological Diversity in the Mediterranean, and signed in Barcelona on 10 June 1995. Moreover, the Mediterranean Basking shark population was added to Appendix II (strictly protected species) of the Bern Convention on the conservation of European Wildlife and Natural Habitats in December 1997.
In order to contribute to the knowledge and conservation of this shark it is important to establish a common procedure to collect data about the specimens that can be accidentally captured or about sightings and stranding in Mediterranean Basin.
In the following sheets we propose a common protocol to collect field dates, to take samples and how to collect them and to measure the different body part of the basking sharks.
We invite all the interested researchers to suggest modification to the present sheets and to put their institute logo in the front page of the document.
Fabrizio Serena and Marino Vacchi
MEDLEM PROGRAM
Data collection field sheet
Accidental capture
Date of capture ______Time of the day ______Depth ______
Latitude ______Longitude ______
Type of Gear ______
Name of the boat ______
Disembark port ______
Leaving animal released Dead animal released Dead animal landed
Weight ______Length ______Sex ______Photos YES NO
Sighting/Stranding
Date ______Time of the day ______Depth ______
Latitude ______Longitude ______
Locality ______Town ______Department ______
Number of animals ______Direction ______
How long is the observation? ______Meteo/Sea state ______
Animal: leaving dead putrefy extremely putrefy body parts
Others information
Stomach contents YES NO
Embryo in the uterusYES NO
(if possible conserve them freezed)
What kind of samples have you taken? ______
______
Is the animal feeding itself? (gill slits completely open!)YES NO
PhotosYES NO VideoYES NO
NOTES ______
______
OBSERVER
Name ______
Complete adress (telephon, e-mail) ______
______
______
Important samples to take and how to conserve them
Alcool 70% / Formalin 4% / Freezed / BouinStomach contents / *** / * / *
Intestine contents / *** / * / *
Gonads / ***
Muscle / *** / *
Liver / ***
Gill and gill-rakers1 / ***
Eye / ***
Vertebra / ***
Skin / ***
Underkin fat / ***
Spermatophores / ***
Parasite / *** / ***
Utera / ***
***Recommended method*Alternative method
1: for the conservation of gills and gill-rakers it will be better to fiss the sample with formalin 10% (formalin and sea water) for a periord of 12-24 h; then rinse the sample with fresh water and store it in alcool 80°.
Technical Terms and Measurements
TOT = total lenghth (snout-posterior tip of the caudal fin)
FOR = fork length (snout-caudal posterior notch)
PRC = precaudal length (snout-precaudal pit, upper origin)
PD2 = pre-second dorsal length (snout-origin second dorsal fin)
PD1 = pre-first dorsal length (snout-origin first dorsal fin)
HDL = head length (snout-5th gill openings)
PBL = prebranchial length (snout-1st gill openings)
POB = preorbital length (snout-anterior eye marging)
PP1 = prepectoral length (snout-origin of the pectoral fin)
PP2 = prepelvic length (snout-origin pelvic fin)
PAL = preanal length (snout-origin anal fin)
Head
EYL = eye length
EYH = eye height
POR = preoral length (snout-mouth)
PRN = prenarial length (snout-nostril)
ING = intergill length (1st-5th gill)
Pectoral fin
P1A = pectoral anterior margin (origin-apex)
P1L = pectoral length (origin-free rear tip)
P1P = pectoral posterior margin (apex-free rear tip)
P1H = pectoral height (apex-insertion)
P1B = pectoral base (origin-insertion)
P1l = pectoral inner margin (insertion-free rear tip)
Dorsal fin
D1A = first dorsal anterior margin (origin-apex)
D1B = first dorsal base (origin-insertion)
D1L = first dorsal length (origin-free rear tip)
D1l = first dorsal inner margin (insertion-free rear tip)
D1P = first dorsal posterior margin (free rear tip-apex)
D1H = first dorsal height (apex-middle point of the base)
1
Caudal fin
CDM = dorsal caudal margin (posterior margin of upper origin
of precaudal pit-posterior tip)
CTR = terminal caudal margin
CST = subterminal caudal margin
CPU = upper postventral caudal margin (subterminal notch-posterior notch)
CPL = lower postventral caudal margin (posterior notch-ventral tip)
CPV = preventral caudal margin (ventral tip-posterior margin
of lower origin of precaudal pit)
Clasper
CLI = clasper inner length
CLO = clasper outer length