4

flyingfish, mackerels, jacks, leatherjackets and occasionally other dolphinfish. Dolphinfish are also extremely fecund. They are capable of spawning during their first year of growth, at about 0.5 m (20 inches) fork length (FL), and individuals may reproduce several times during a single spawning season. Peak spawning in Florida occurs from December through May although reproductively active females have been observed during all months of the year.

Biologists at the Florida Marine Research Institute (www.floridamarine.org) have been recently investigating the life cycle of dolphinfish, and you may have encountered them at fishing tournaments where they have collected valuable samples for such research. This research was supported by Sportfish Restoration Funds (federalaid.fws.gov/sfr/fasfr.html) awarded to the Florida Fish and Wildlife Conservation Commission (www.floridaconservation.org). Results from this study show that egg output of dolphinfish increases rapidly in relation to female size. For example, last April (2002) we collected a 1.2 m (47 inch) FL female at the Beau Franklin tournament in Port Canaveral that had over 600,000 eggs ready to spawn! One new outcome of this recent research at FMRI concerns dolphinfish’s size at maturity, which will be estimated based on hundreds of histological preparations of gonad tissue. Minimum-size limits are typically set in relation to size at maturity to promote egg output for maintaining a living (=renewable) marine resource. This size at maturity data will be of interest to anglers and managers alike, because both parties have expressed concern about the lack of a minimum size limit for recreational dolphinfish catches.

      Presently there is no minimum size limit on recreational catches, although a recent draft of the dolphinfish Fishery Management Plan proposes a recreational fish size limit comparable to the existing commercial fish size limit along with both recreational and commercial catch limits (see winter 2003 newsletter at www.safmc.net). Anglers encountered in marinas and on the web are talking about a 24” minimum-size limit

 

 

 

 and about lowering the bag limit from 10 to 5 fish. Considering that dolphinfish can grow so fast, a minimum size limit may help improve the fillet size for the average fish harvested. For example, if a 20” fish is released in late summer, it may be 10” longer in only a couple of months. If too many small fish are taken then this leads to a condition called growth overfishing. Did you say that you don’t believe that you will have a chance to catch that fish again in the open ocean? Well, consider that data from Mote Marine Lab (www.mote.org) indicates that a remarkably high percentage (5%) of dolphinfish tagged and released in the open ocean were recaptured! The unusually fast growth rate of dolphinfish and the high turnover (=short age) of dolphinfish populations should make them less susceptible to over-fishing than other longer-lived, slower maturing species. But this is not a free pass to anglers for unchecked fishing pressure. In terms of dolphinfish fishing, the frenzy of fishing on a large group of ‘schoolies’ is an outstanding memory for many offshore anglers, but it is precisely this situation that is the Achilles’ heel of the dolphinfish fishery. If these schoolies are ‘peanut’ sizes, then unrestrained fishing effort can lead to growth overfishing. In fact, this behavior makes this species vulnerable to overfishing, because these ‘schoolies’ will typically stay close to a fishing vessel if at least one fish is kept in the water. It does appear that many of Florida’s sport anglers are ready for the proposed regulations; this should be good for dolphinfish and the fishery.

 

 If you would like to contact Rich McBride, he can be reached via email at Richard.McBride@fwc.state.fl.us.

 

 

[ Page 1 | Page 2 | Page 3 | Page 4 | Page 5 | Page 6 | 

Page 7 ]