Artificial reefs are commonly used to provide structured habitat in areas with limited natural habitat to enhance the environment. Creating artificial reefs is expensive, and materials are often limited; thus, discussions are needed regarding the best material and design to maximize reefing efficiency while best meeting the goal of reefing programs. We tracked Red Snapper Lutjanus campechanus, an economically important and reef-dependent species, by using a Vemco Positioning System to determine fine-scale movements and habitat use around a nearshore reef comprised of three types of reefing structure: concrete reef pyramids, concrete culverts, and a sunken ship. Habitat use (core volume and home range, or the probability of a fish being absent 50% or 5% of the time, respectively) was significantly different by month, with the largest movements during summer months. Mean depth values also differed by study month (February-August), with Red Snapper residing deepest in the water column during August and shallowest during April. In the summer months, differences among structure types were observed in core volume use but not home range, suggesting that Red Snapper used similar-sized areas on all three structure types. A high reported recapture rate (77%; 10 of 13 fish) indicated that these easily accessible nearshore reefs undergo heavy fishing pressure. Half of the recaptures were reported as recaptured on a structure other than their tagging structure; however, tagged fish spent the greatest percentage of time on their tagging structure. Red Snapper habitat use was influenced more by the presence of structure than by the type of reefing structure. Using the results from this study combined with a cost comparison of reef types, we argue that use of the least expensive reefing material that covers the largest area may be the best policy in designing future artificial reefs.
The practice of catch and release fishing is common among anglers but has been shown to cause unintended mortalities in some species. Current post-release mortality estimates used in coastal shark stock assessments are typically derived from boat-based shark fisheries, which differ from shore-based operations that expose sharks to potentially more stressful environmental and handling conditions. Recreational post-release mortality rates in shore-based fisheries must be quantified to improve stock assessment models and to create guidelines that protect species from overexploitation. Here, we partnered with experienced anglers acting as citizen scientists to deploy pop-up satellite archival transmitting tags (PSAT, n = 22) and acceleration data loggers (ADLs, n = 22). on four commonly caught sharks including the blacktip shark (Carcharhinus limbatus, n = 11), bull shark (Carcharhinus leucas, n = 14), tiger shark (Galeocerdo cuvier, n = 6), and great hammerheads (Sphyrna mokarran, n = 2). Mortality occurred within minutes to hours post-release. If evidence of mortality occurred after normal diving behavior had been re-established for 10 days, then the mortality was considered natural and not related to the catch-and-release process. Post-release mortality estimates ranged from 0% for bull and tiger sharks to 45.5% for blacktip sharks. Of the two great hammerheads, one died within 30 minutes post-release while the other exhibited mortality characteristics 14 days after release. Moribund blacktip sharks experienced on average 3.4–4.9°C warmer water compared with survivors. Recovery periods were estimated for survivors of each species and were highly variable, differing based on duration of tag deployment. High variability in responses to capture and release between species demonstrates the need for species-specific assessments of post-release mortality in shore-based recreational fisheries.
Post‐release mortality threatens shark populations already imperiled by overfishing, capture stress, and a changing climate. Few studies have quantified post‐release mortality for sharks captured in land‐based recreational fisheries. From 2018 to 2021, a land‐based shark post‐release mortality study was conducted and identified water temperature and species‐specific behavior as contributing factors to post‐release mortality. The purpose of this study was to estimate the effectiveness of disseminating the recommendation for best practices to recreational shark anglers and to determine if this information influenced angler behavior. Awareness of our post‐release mortality study influenced an angler's likely release behavior, with an increase in sharks landed in the water and corresponding decrease of sharks landed on dry sand. This study demonstrated direct evidence of conservation‐based changes in angler behavior following effective research communication and involvement of anglers in research. Outreach and engagement initiatives aimed at providing best handling practices to recreational anglers should be easily digestible, widely available, and an important component of future research.
Meteorological disturbances, such as hurricanes, can cause wide distributional changes to fish populations, but studies documenting fish movement in response to these disturbances are rare and serendipitous. We opportunistically examined how a hurricane influenced behavior of Red Snapper Lutjanus campechanus at an artificial reef complex in the western Gulf of Mexico. Red Snapper had a variety of responses, with some fish emigrating and some remaining on site during Hurricane Harvey—a category 4 storm. Hurricane‐induced destruction or alteration of habitat may alter space use behavior of fish. However, caution should be used when interpreting behavior without the inclusion of array performance, which may change due to environmental conditions. Importantly, when acoustic array efficiency was not accounted for in space use analyses, mean kernel utilization distribution (m3) was marginally different among the periods before, during, and after Hurricane Harvey. However, when mean daily array efficiency was included as a covariate, space use among the three periods was not significantly different. Hurricanes can affect the movement and residency of marine species and can be an important driver in the displacement of populations and degradation of habitats, but array efficiency should be incorporated to prevent misinterpreting the behaviors of tagged fish.
Nearly half of the over 400 North American crayfish species are imperiled and need some level of protection to ensure sustainable populations, but the detailed life histories of only about 12% of these crayfishes have been published. We provide needed baseline information on the reproductive biology of the Sly Crayfish, Procambarus versutus (Hagen, 1870), through sampling a small stream monthly (N = 23 samples) in the Choctawhatchee River watershed, southeastern Alabama, USA for two years. We collected data on 2,026 individuals (mean 88 sample–1) over the duration of the study and found minimum size at sexual maturity to be 18.3 mm for both males and females. Life cycles were consistent across both years with a major peak in reproductively active males in June and reproductively active females in July. Reproductively-active males and females were nevertheless collected nearly year-round, suggesting continuous low levels of reproduction throughout a given year, with three peaks in reproduction that vary in magnitude. Only three ovigerous females were collected over the study period, possibly because ovigerous females become reclusive and inactive, therefore difficult to collect. The maximum brood size sampled was 242 eggs female–1. There was no evidence for distinct age classes, likely due to year-round reproduction. Similar regional species with detailed information on reproductive biology available have reproduction patterns similar to those in our data. The information herein contributes to the largely lacking information on the life history of North American crayfishes and emphasizes the need to further evaluate the reproductive biology of species lacking sufficient data to aid conservation efforts.
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