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Growth models describe the change in length or weight as a function of age. Growth curves in tunas can take different forms from relatively simple von Bertalanffy growth curves (Atlantic bluefin, albacore tunas) to more complex two- or three-stanza growth curves (yellowfin, bigeye, skipjack, southern bluefin tunas). We reviewed the growth of the principal market tunas (albacore, bigeye, skipjack, yellowfin and the three bluefin tuna species) in all oceans to ascertain the different growth rates among tuna species and their implications for population productivity and resilience. Tunas are among the fastest-growing of all fishes. Compared to other species, tunas exhibit rapid growth (i.e., relatively high K ) and achieve large body sizes (i.e., high L ∞ ). A comparison of their growth functions reveals that tunas have evolved different growth strategies. Tunas attain asymptotic sizes ( L ∞ ), ranging from 75 cm FL (skipjack tuna) to 400 cm FL (Atlantic bluefin tuna), and reach L ∞ at different rates ( K ), varying from 0.95 year −1 (skipjack tuna) to 0.05 year −1 (Atlantic bluefin tuna). Skipjack tuna (followed by yellowfin tuna) is considered the “fastest growing” species of all tunas. Growth characteristics have important implications for population dynamics and fisheries management outcomes since tunas, and other fish species, with faster growth rates generally support higher estimates of Maximum Sustainable Yield (MSY) than species with slower growth rates.

Atlantic bluefin tuna populations are in steep decline, and an improved understanding of connectivity between individuals from eastern (Mediterranean Sea) and western (Gulf of Mexico) spawning areas is needed to manage remaining fisheries. Chemical signatures in the otoliths of yearlings from regional nurseries were distinct and served as natural tags to assess natal homing and mixing. Adults showed high rates of natal homing to both eastern and western spawning areas. Trans-Atlantic movement (east to west) was significant and size-dependent, with individuals of Mediterranean origin mixing with the western population in the U.S. Atlantic. The largest (oldest) bluefin tuna collected near the northern extent of their range in North American waters were almost exclusively of western origin, indicating that this region represents critical habitat for the western population.

Data sets from three laboratories conducting studies of movements and migrations of Atlantic swordfish (Xiphias gladius) using pop-up satellite archival tags were pooled, and processed using a common methodology. From 78 available deployments, 38 were selected for detailed examination based on deployment duration. The points of deployment ranged from southern Newfoundland to the Straits of Florida. The aggregate data comprise the most comprehensive information describing migrations of swordfish in the Atlantic. Challenges in using data from different tag manufacturers are discussed. The relative utility of geolocations obtained with light is compared with results derived from temperature information for this deep-diving species. The results show that fish tagged off North America remain in the western Atlantic throughout their deployments. This is inconsistent with the model of stock structure used in assessments conducted by the International Commission for the Conservation of Atlantic Tunas, which assumes that fish mix freely throughout the North Atlantic.

Stable carbon (Δ13C) and oxygen (Δ18O) in the otolith cores of Atlantic bluefin tuna (Thunnus thynnus) vary temporally, with changes that quantitatively follow interdecadal variation in atmospheric and oceanic reservoirs. Both carbon and oxygen isotopic signatures vary significantly by year of birth over the range investigated (1947‐2006), with Δ13C decreasing and Δ18O increasing (‐2.56 × 10−2‰ and 4.3 × 10−3‰ yr−1, respectively). The rate of change in otolith Δ13C was similar to reported rates of atmospheric Δ13C depletion, attributed to deforestation and the burning of fossil fuels (referred to as the Suess effect), suggesting a close link between atmospheric and oceanic carbon pools. Increases in otolith Δ18O were evident but less pronounced, with observed variation possibly attributable to changing salinity in the Atlantic Ocean. Otolith cores of bluefin tuna effectively track interdecadal trends and record past seawater Δ13C and Δ18O.

Stable carbon (δ¹³C) and oxygen (δ¹ɸO) in the otolith cores of Atlantic bluefin tuna (Thunnus thynnus) vary temporally, with changes that quantitatively follow interdecadal variation in atmospheric and oceanic reservoirs. Both carbon and oxygen isotopic signatures vary significantly by year of birth over the range investigated (1947–2006), with δ¹³C decreasing and δ¹ɸO increasing (- 2.56 × 10 ¯ 2 ‰ and 4.3 × 10⁻³% o yr⁻¹, respectively). The rate of change in otolith δ¹³C was similar to reported rates of atmospheric δ¹³C depletion, attributed to deforestation and the burning of fossil fuels (referred to as the Suess effect), suggesting a close link between atmospheric and oceanic carbon pools. Increases in otolith δ¹ɸO were evident but less pronounced, with observed variation possibly attributable to changing salinity in the Atlantic Ocean. Otolith cores of bluefin tuna effectively track interdecadal trends and record past seawater δ¹³C and δ¹ɸO.

Stable carbon (d super(13)C) and oxygen (d super(18)O) in the otolith cores of Atlantic bluefin tuna (Thunnus thynnus) vary temporally, with changes that quantitatively follow interdecadal variation in atmospheric and oceanic reservoirs. Both carbon and oxygen isotopic signatures vary significantly by year of birth over the range investigated (1947-2006), with d super(13)C decreasing and d super(18)O increasing (-2.56 x 10 super(-2)ppt and 4.3 x 10 super(-3)ppt yr super(-1), respectively). The rate of change in otolith d super(13)C was similar to reported rates of atmospheric d super(13)C depletion, attributed to deforestation and the burning of fossil fuels (referred to as the Suess effect), suggesting a close link between atmospheric and oceanic carbon pools. Increases in otolith d super(18)O were evident but less pronounced, with observed variation possibly attributable to changing salinity in the Atlantic Ocean. Otolith cores of bluefin tuna effectively track interdecadal trends and record past seawater d super(13)C and d super(18)O.

Data sets from three laboratories conducting studies of movements and migrations of Atlantic swordfish (Xiphias gladius) using pop-up satellite archival tags were pooled, and processed using a common methodology. From 78 available deployments, 38 were selected for detailed examination based on deployment duration. The points of deployment ranged from southern Newfoundland to the Straits of Florida. The aggregate data comprise the most comprehensive information describing migrations of swordfish in the Atlantic. Challenges in using data from different tag manufacturers are discussed. The relative utility of geolocations obtained with light is compared with results derived from temperature information for this deep-diving species. The results show that fish tagged off North America remain in the western Atlantic throughout their deployments. This is inconsistent with the model of stock structure used in assessments conducted by the International Commission for the Conservation of Atlantic Tunas, which assumes that fish mix freely throughout the North Atlantic.

Recently-settled 0-group juvenile cod Gadus morhua and haddock Melanogrammus aeglefinus were observed by submersible dives and research bottom trawls to inhabit primarily a large pebble-gravel deposit located on the northeastern edge of Georges Bank at 70 to 100 m water depth. Pelagic juvenile gadids are widespread on the bank in late spring, but by late July, they have become demersal and are abundant only on the gravel bed. Coloration of the juveniles mimics the appearance of the pebble bottom, possibly making them less vulnerable to predation there than on the light-colored sand bottom of most areas of the bank. On the basis of these observations, we hypothesize that the gravel habitat favors their survival through predator avoidance and, possibly to a lesser extent, through increased prey abundance. In particular, the pebble-gravel deposit on northeastern Georges Bank supports the largest aggregations of demersal juveniles, and it may be essential to the recruitment success of the Georges Bank gadid population. By September, the young fish are no longer present on the gravel bed because night-time feeding forays off the bottom result in their transport southeastward in the clockwise current gyre on the bank. The study area is characterized by strong, rotary tidal currents. During the day, demersal juveniles remain within a few centimeters of the bottom in the boundary layer where currents are somewhat reduced and where they maintain their position by swimming continually into the current. At night, regardless of the current, they rise off the bottom to feed on invertebrates in the near-bottom water column. Abundance estimates of demersal juveniles based on research bottom trawls show variability related to fish size and time of day. When compared with estimates of juvenile abundance based on submersible observations, the trawl data underestimate the numbers of juvenile fish present. We expect a knowledge of the diel behavior, geographic location, and most favorable habitat of demersal 0-group juveniles will aid in the assessment and management of the Georges Bank gadid population.