Gray snapper3/13/2023 ![]() Mean size-at-age was significantly different between regions for ages 4 – 9, (92% of total samples). The von Bertalanffy growth equations were Lt = 365 (1 - e-0.35 (t + 1.37)) (n = 559) for all areas combined, Lt = 365 (1 - e-0.55(t + 0.00)) (n = 185) for fish from North Carolina through Cape Canaveral, Florida, and Lt = 368 (1 - e-0.25 (t + 2.51)) (n = 374) for fish from southeast Florida. Ages ranged from 2 – 19 years, and the largest fish measured 513 mm TL (total length, mm). Opaque zones were annular, forming April – July (peaking in June). commercial and recreational fisheries from 1975 – 2017 were determined using sectioned otoliths. ![]() Population expansion could be facilitated by management measures that improve overwinter survival of juveniles and subadults in estuaries prior to offshore recruitment.Īges of whitebone porgy (Calamus leucosteus) (n = 559) from southeastern U. Increasing abundance coupled with an expanding age structure of Gray Snapper in Texas have co-occurred with increasing winter temperatures over time. Comparison of size (total length in mm) of recreational catch inshore versus offshore suggests that mature adults recruit to offshore habitats around 409 mm TL, or around 3 years old, which is approximately coincident with the onset of sexual maturity. Gray Snapper juveniles and subadults encountered in Texas estuaries are generally associated with lower bays and offshore passes, and are more common in the late summer/early fall. Increasing Gray Snapper abundance in Texas was coupled with expansion of the population age structure in comparisons before and after 1993. Estuarine Gray Snapper were subsequently sampled from gill nets, and otolith age and gonad development were evaluated microscopically to assess patterns of age, growth, and maturity. Boosted regression trees (BRT) were used to evaluate factors (water quality, season, depth, bay and inlet distance) driving Gray Snapper presence in fishery independent samples of juveniles (seines) and subadults (gill nets) found in estuaries. We assessed long term trends in distribution and abundance of Gray Snapper in Texas using fishery dependent and fishery independent data collected by the Texas Parks and Wildlife Department in the years 1980 - 2019. Recent population expansion of Gray Snapper, Lutjanus griseus, in the northern Gulf of Mexico is driving increasing catch in the recreational fishery in Texas. Estimates of F for gray snapper by area were 0.16 for north Florida and 0.66 for south Florida. Recruitment to the fisheries occurred between ages 5 and 8 for north Florida and ages 4 and 5 for south Florida. Estimates of Z averaged 0.34 for north Florida and 0.95 for south Florida. Estimates of M ranged from 0.14 to 0.43 for north Florida and from 0.29 to 0.38 for south Florida. Mean lengths at age from back-calculations to the last annulus ranged from 121 mm at the end of age 1 to 740 mm at age 24 for north Florida, and 227 mm at age 2 to 495 mm at age 15 for south Florida. Weight-length relations were significantly different (F=39.198, P<0.001, df=10,705) for fish measured from the headboat survey from 1982-97 between north Florida (W=8.4 × 10-9 × T元.08, n=4034) and south Florida (W=5.45 × 10-9 × T元.15, n=6670), where W = total weight (kg). Weight-length relations were not significantly different by sex. The oldest fish examined was 24 years old and measured 760 mm TL. Marginal increment analysis on sectioned otoliths (n=1243) confirmed annulus formation in June and July. Fish were weighed (g) and measured (total length, TL, in mm), and sagittal otoliths were removed for aging. Gray snapper, Lutjanus griseus, were sampled from recreational headboat and commercial landings along the east coast of Florida, 1994-97.
0 Comments
Leave a Reply.AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |