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Nonlethal age-estimation methods for Florida Bass Micropterus salmoides using fin rays and spines would enhance trophy-bass research, management, and conservation. Nonlethal removal of fin structures would also expand opportunities for collecting age-related information, specifically during small-population projects as well as tournaments and citizen-science programs, for which sacrificing fish is not an option. We assessed the bias of age estimates derived from Florida Bass anal-, pelvic-, dorsal-, and pectoral-fin rays and anal-, pelvic-, and dorsal-fin spines by comparing them to age estimates derived from otoliths (i.e., sagittae), which are the standard for aging Florida Bass. We evaluated the precision of age estimates by calculating the absolute difference between replicate reads of each aging structure for each reader. Linear-mixed effects model selection indicated that precision was most affected by age, structure, and the age*structure interaction, in which the effect of age varied by structure. Age estimates from otoliths were the most precise, whereas pelvic spines were the least precise among all structures examined. Bias was similar across all fin structures, but the effect of age on bias varied by reader. Marginal increment analysis indicated that annulus formation was completed from November to March in Florida Bass dorsal spines, 5 mon earlier than in Florida Bass otoliths. Our results suggest that nonlethally removed fin structures, especially dorsal spines, have potential for use in estimating age, growth rates, mortality, and age structure of bass populations, which could be particularly beneficial where bass can reach unusual trophy sizes. [ABSTRACT FROM AUTHOR]

Effective management of a species requires that resource managers know critical aspects of its ecology, including information on home range and habitat use. We conducted the first telemetry study on the Suwannee alligator snapping turtle (Macrochelys suwanniensis), and we examined movements at an upper river (UR) site and a lower river (LR) site in the Suwannee River in Florida, USA. We estimated home range size with kernel density estimates (KDE) using the FishTracker GIS toolbox, and we examined potential differences in KDEs with Generalized Linear Models (GLMs). We also used GLMs (family = binomial) to examine habitat selection for M. suwanniensis. We used an information-theoretic approach to rank and select the most parsimonious models. Overall, our models revealed that M. suwanniensis possessed larger 90% KDEs in the LR site than the UR site, and in both sites, turtles moved into the floodplain during flooded conditions. Remarkably, these movements continued even after water levels receded and the aquatic links were severed. Interestingly, M. suwanniensis selected shallow water with some type of subsurface cover, especially large woody debris (LWD). Instream LWD is likely extremely important, especially during low water levels when undercut banks and other bank habitats are unavailable, so the removal of LWD, including deadhead logs, could negatively affect the species. Minimum flows have been established in the drainage, but river water levels have declined an estimated 40% since human settlement, partly because of groundwater withdrawal outside the drainage, potentially imperiling this state Threatened species. [ABSTRACT FROM AUTHOR]

Largemouth Bass Micropterus salmoides, Florida Bass Micropterus floridanus, and their intergrade are socially and economically valuable sport fish. In the southeastern United States, it is customary for fisheries personnel to age black bass Micropterus species using sagittal otoliths, which requires killing the fish. Presently, fisheries managers and black bass anglers show reluctance to sacrifice large individuals. Development of a nonlethal ageing technique would not only allay concerns of sacrificing large black bass, but it could offer a pathway for new research, management, and conservation. We excised dorsal spines III–V from Largemouth Bass in Florida varying from 30 to 57 cm total length to evaluate the effects of the procedure on survival over 35 d. No mortalities were observed for fish with excised dorsal spines, and experiment-wide survival was 0.94 (0.87–1.00; 95% confidence interval). No significant differences in survival, weight change, or incidence of external injuries were observed between control and excised fish. The areas of spine excision healed with no visible infection or inflammation at the conclusion of the experiment. Therefore, dorsal spine removal offers managers a nonlethal option for collecting ageing structures of adult Largemouth Bass in Florida, including large individuals, and this result likely extends to other Micropterus species as well. [ABSTRACT FROM AUTHOR]

Data on Karenia brevis red tides (≥105 cells l-1) and on dead or debilitated (i.e. stranded) Kemp's ridleys Lepidochelys kempii, loggerheads Caretta caretta, green turtles Chelonia mydas, hawksbills Eretmochelys imbricata, and leatherbacks Dermochelys coriacea documented in Florida during 1986-2013 were evaluated to assess red tides as a sea turtle mortality factor. Unusually large numbers of stranded sea turtles were found coincident with red tides primarily along Florida's Gulf coast but also along a portion of Florida's Atlantic coast. These strandings were mainly adult and large immature loggerheads and Kemp's ridleys, and small immature green turtles and hawksbills. Unusually large numbers of stranded leatherbacks never coincided with red tide. For the 3 most common species, results of stranding data modeling, and of investigations that included determining brevetoxin concentrations in samples collected from stranded turtles, all indicated that red tides were associated with greater and more frequent increases in the numbers of stranded loggerheads and Kemp's ridleys than in the number of stranded green turtles. The mean annual number of stranded sea turtles attributed to K. brevis red tide was 80 (SE = 21.6, range = 2-338). Considering typical stranding probabilities, the overall mortality was probably 5-10 times greater. Red tide accounted for a substantial portion of all stranded loggerheads (7.1%) and Kemp's ridleys (17.7%), and a smaller portion of all stranded green turtles (1.6%). Even though K. brevis red tides occur naturally, the mortality they cause needs to be considered when managing these threatened and endangered species.