Documentation of Atlantic Tarpon (Megalops atlanticus) Space Use and Move Persistence in the Northern Gulf of Mexico Facilitated by Angler Advocates

Atlantic tarpon (Megalops atlanticus, hereafter tarpon) are facing a multitude of stressors and are considered Vulnerable by the IUCN; however, significant gaps remain in our understanding of tarpon space use and movement. From 2018 to 2019, citizen scientists facilitated tagging of 23 tarpon with SPOT tags to examine space use and movement across the northern Gulf of Mexico. Movement-based kernel densities were used to estimate simplified biased random bridge-based utilization distributions and a joint move persistence model was used to estimate a behavioral index for each fish. Tarpon showed consistent east–west movement from the Alabama/Florida border to Louisiana, and utilization distributions were highest in the Mississippi River Delta. Move persistence was highest in Alabama and Mississippi and lowest in Louisiana. Our examination of tarpon space use and movement indicates that Louisiana is a critical, yet understudied, part of their range

Spatiotemporal Dynamics of Mediterranean Shallow Coastal Fish Communities Along a Gradient of Marine Protection

The importance of habitat factors in designing marine reserves and evaluating their performance over time has been regularly documented. Over three biennial sampling periods, we examined the effects of vegetated coverage and habitat diversity (i.e., patchiness) on fish density, community composition, and species-specific patterns along a gradient of protection from harvest in the shallow Spanish southern Mediterranean, including portions of the Tabarca marine reserve. With the exception of two herbivores (Sarpa salpa and Symphodus tinca), vegetated cover did not significantly affect fish densities, while habitat diversity was an influential factor across all three sampling periods. Overall, fish density was more positively associated with more continuous vegetated or unvegetated habitats, and was greatest in areas of highest protection (Tabarca II – Isla Nao site). These patterns were usually observed for four abundant fish species (Boops boops, Chromis chromis, Oblada melanura, and S. salpa). Fish community composition was distinct in the most protected portion of the Tabarca reserve, where it was also most stable. Our findings align with previous investigations of the Tabarca reserve and its surrounding areas, and demonstrate its continued effectiveness in conserving fish biomass and habitat. Together with effective management, marine reserves can facilitate greater species abundance, more stable biological communities, and resilient ecosystems

Evaluating protected species bycatch in the U.S. Southeast Gillnet Fishery

•Incidental catch in gillnets is a threat to many marine taxa, particularly threatened or endangered species.•Factors that influenced protected species bycatch in U.S. SE Gillnet Fishery were modeled.•Zero-inflated negative binomial identified factors associated with incidental capture to be species-specific.•Identified factors associated with incidental capture can aid fishery managers in species-specific mitigation strategies. Incidental capture or ‘bycatch’ of non-targeted species is a global fisheries issue that threatens ocean ecosystems and the conservation and recovery of protected species. Many protected species are at a high risk of incidental capture and mortality in commercial fisheries, which could have an impact on already decreasing populations. From 1998 to 2017, U.S. federal fisheries observers aboard fishing vessels in the U.S. Southeast Gillnet Fishery collected data on captures of encountered protected species. Data collected by the observers were used to describe protected species incidental capture within this fishery. A generalized linear zero-inflated negative binomial two-part model (GLM-ZINB) was applied to determine which environmental and fishing characteristic factors influence the probability of incidental capture of protected species including leatherback, Dermochelys coriacea, and loggerhead, Caretta caretta, sea turtles, bottlenose dolphins, Tursiops truncatus, and giant manta ray, Manta birostris. While a variety of factors were considered in our models, no one single factor was found to influence all protected species. Incidental capture of leatherback turtles was influenced by season, depth, and gillnet depth, while loggerhead turtles were influenced by season, sea surface temperature, and target species of the fishery. Bottlenose dolphin bycatch was most influenced by soak duration, gear type, and season, while giant manta ray captures were influenced by soak duration, gear type, and depth. Environmental factors and fishing characteristics associated with incidental capture of protected species can be used to help guide fishery managers as to what species-specific regulations could be implemented to help mitigate capture

Bonefish do not respect international borders: the Florida–Bahamas connection

Migratory connectivity of marine fishes is difficult to quantify yet critical for effective species management. Anchor tagging and acoustic telemetry tracking projects on bonefish ( Albula vulpes ), an economically important coastal exploited species, discovered three bonefish that moved from coastal waters of the Florida Keys to Andros Island, Bahamas. The anchor tagging project had two bonefish make this Florida–Bahamas movement and the acoustic telemetry project had one bonefish make this movement. Outlier analysis was done on the linear distance of these three Florida–Bahamas movements compared to the linear distances of bonefish tagged and recaptured in Florida waters. Also, comparisons were made between the mean distances between tagging locations and mean distances between recapture locations to evaluate whether relocations were active or passive. The linear distance analysis determined the three Florida–Bahamas movements were not outliers. Second, the mean distance between the tagging locations in Florida coastal waters (111 km; 95% CI 63.7–158.4 km) and the mean distance between recapture locations in Andros Island coastal waters (30 km; 95% CI 25.0–35.0 km) may suggest that these relocations are not random dispersal. This paper provides evidence that bonefish can make long distance movements (> 100 km) over deep water (> 200 m). This evidence suggests the need for more research to evaluate the potential for connectivity between neighboring nations for bonefish

Horizontal and vertical movements of immature dusky sharks Carcharhinus obscurus in relation to commercial longline fisheries in the western North Atlantic Ocean

Background Many species of sharks, including the dusky shark Carcharhinus obscurus, are often incidentally captured in commercial pelagic and bottom longline fisheries. Incidental capture can lead to at-vessel or post-release mortality and can be detrimental to populations of threatened, endangered, or prohibited species. The estimated at-vessel mortality for dusky sharks can be high in longline fisheries and, to minimize mortality, time-area closures have been designated in the western North Atlantic Ocean to mitigate interactions with longline fisheries, yet incidental capture of dusky sharks is still common. We compared the vertical and horizontal movements of dusky sharks to the overall fishing effort and depth fished of commercial pelagic and bottom longline fisheries to determine when and where overlap is present that could lead to incidental capture. Results Twenty-one (n = 21) dusky sharks were tagged with pop-up archival transmitting satellite tags and all were immature animals (123-200 cm FL) apart from two individuals (230 and 300 cm FL). Sharks were tagged off the coasts of North Carolina (71%) and Florida (29%). Twenty tags (95%) reported and provided tracks between 1 and 107 days (median 15 days) and 10 tags (50%) remained on sharks for > 4 days. Most individuals remained within the bottom longline closed area off the coast of North Carolina during their time at liberty. Dusky sharks primarily occupied the 20-40 m depth range 26% of the time, and overlapped with bottom and pelagic longline gears 41% and 59% of the time, respectively. Overlap was highest in the winter and spring for both commercial fisheries. Conclusions The use of archival satellite telemetry in this study has provided valuable preliminary information on vertical and horizontal movements of immature dusky sharks in western North Atlantic Ocean. Dusky sharks may be more vulnerable to incidental capture in the pelagic longline fishery due to the high fishing effort, larger areas of horizontal overlap, and greater percentage of vertical overlap. This information will inform mitigation measures of commercial longline fisheries, which can work toward population rebuilding of the species

Tracking public interest and perceptions about smalltooth sawfish conservation in the USA using Instagram

The population of smalltooth sawfish (Pristis pectinata) in the USA was listed as endangered under the US Endangered Species Act in 2003. Based on objectives identified in the Smalltooth Sawfish Recovery Plan, an interdisciplinary team developed a variety of outreach efforts and products to educate the public and promote sawfish conservation. These include safe viewing, handling, release, and reporting guidelines for boaters, divers, and anglers that may interact with the species. The usefulness of monitoring social media to track public interest and perceptions of smalltooth sawfish was investigated via Instagram posts mentioning sawfish encounters in the USA. We aimed to identify how current outreach efforts and messaging can be improved and expanded to better inform the public and promote positive change in their behaviour to further protect smalltooth sawfish. All encounters occurred in Florida waters and the trend of sawfish‐related Instagram posts increased congruently with traditionally reported sawfish encounters from 2012 to 2019. The number of Instagram users who indicated that they reported their encounter or that any sawfish encounter should be reported has increased, suggesting outreach efforts have gained traction and that some members of the public are actively promoting sawfish conservation through encounter reporting. The overall tone, and thereby public perception of and attitude towards sawfish, was largely positive. Though social media can be used to guide outreach initiatives and provides a platform for researchers to engage large public audiences, future research efforts should include electronic surveys within the recreational, commercial, diving, and angling communities. Additionally, social media posts should be compared with traditionally reported encounters, and media professionals working with scientists should focus on increasing the utility of social media as a way to collect encounter reports and create engaging educational content to be included with continued outreach efforts throughout the south‐eastern USA

Historical specimens and photographs reveal long-term changes in Smalltooth Sawfish (Pristis pectinata) age class distribution and average size during US population decline

1. Population-level, historical studies can provide insights on the distribution, abundance and demographic characteristics of imperiled species prior to human exploitation, habitat modification or climate change. These studies provide a baseline for contemporary data, which often shape successful management and recovery. 2. The smalltooth sawfish (Pristis pectinata) occupies similar to 20% of its historical range due to declines driven primarily by mortalities in fisheries and coastal habitat loss over the last century. As a result, they are listed as Critically Endangered on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species and as Endangered federally in the United States (U.S.). 3. Because P. pectinata grow to a large size and have a toothed rostrum, many historical photographs and specimens are archived in natural history collections. Metadata and morphometric data were collected and analysed from P. pectinata photographs (n = 84) and specimens (n = 429) to evaluate temporal changes in average size and historical distribution of five age classes in U.S. waters. 4. Historically, smaller age classes were well-distributed throughout the northern Gulf of Mexico, while only larger age classes were recorded on the U.S. east coast, north of Florida. All age classes were found in both Florida and Texas historically, but records from Texas decline after the 1980s and remain persistent in Florida, indicative of a strong-hold for the U.S. population. Regardless of origin, individuals in three of the five age classes were larger on average historically than those observed today. 5. Understanding which age classes used previously occupied areas will help direct habitat restoration efforts and support recovery, especially in the face of climate change. Non-traditional data sources, such as those used here, may often be the only means of providing historical context to modern research on imperiled species, ultimately guiding restoration and conservation efforts

Large-scale space use of large juvenile and adult smalltooth sawfish Pristis pectinata: implications for management

The smalltooth sawfish Pristis pectinata is an endangered species endemic to the Atlantic Ocean. The only known viable populations occur in the USA along both coasts of Florida and in the western Bahamas. Little is known about habitat use and movement ecology of large juvenile and adult smalltooth sawfish. Although Critical Habitat- a management designation in the USA- has been identified for small juveniles, it has yet to be identified for these life stages. Between May 2016 and April 2019, we used passive acoustic telemetry and 3 large data sharing networks of receivers to track movements of 43 large juvenile and adult smalltooth sawfish. During this study, 24 females and 19 males were implanted with transmitters with estimated 4 or 10 yr battery lives. These tagged individuals were detected off the southeastern USA on 461 receivers ranging from off the coast of Brunswick, Georgia, to the lower Florida Keys, and along the Gulf coast to Apalachee Bay, Florida. Seasonal migrations were undertaken by 58% (43% mature; 57% immature) of the tagged individuals, with the remainder being apparent residents of their tagging locations. Tagged sawfish from both size classes and of both sexes migrated, which indicates that neither sex nor length is a predictor of whether a sawfish will migrate or not. Although both coasts of Florida were used for migration, most individuals consistently used the same coast when they migrated. The areas surrounding Boca Grande, Cape Canaveral, and the lower Florida Keys were heavily visited sites that could be further evaluated as potential Critical Habitat for these life stages. Understanding the movement patterns of this Critically Endangered species is essential for creating policies to protect areas important for promoting growth of the population

Commercial fishery bycatch risk for large juvenile and adult smalltooth sawfish (Pristis pectinata) in Florida waters

Incidental catch of marine species can create ecological and economic issues, particularly for endangered species. The smalltooth sawfish (Pristis pectinata) is endemic to the Atlantic Ocean and listed as Endangered in the US Endangered Species Act. One of its major threats is bycatch mortality in commercial fisheries. Despite the protection afforded by the US Endangered Species Act, smalltooth sawfish are still captured as bycatch in commercial fisheries. Acoustic and satellite tag data collected on 59 sawfish between 2011 and 2019 were analysed to assess commercial fishery bycatch risk for large juveniles and adults off Florida. This study focused on shrimp trawl, south‐east coastal gillnet, and shark bottom longline fisheries, as these were identified in the recovery plan as having the greatest potential threats to recovery. Bycatch risk associated with the shrimp trawl fishery was significantly higher than the other fisheries, indicating that this fishery currently poses the greatest threat to recovery. Bycatch risk was concentrated in all seasons in the Gulf of Mexico adjacent to the lower Florida Keys for the shrimp trawl fishery, off Cape Canaveral in the south‐east coastal gillnet fishery, and in the Atlantic Ocean adjacent to the Florida Keys in the shark bottom longline fishery. Tagging location and sex were predictors of bycatch risk. Individuals tagged in Charlotte Harbor had the highest shrimp trawl bycatch risk. Females tagged in south Florida tended to reside in the deepest water, which is where shrimp trawl effort is highest. Therefore, females may be at more risk in these deeper waters. Results from this study indicate a year‐round closure of waters off south‐west Florida to the shrimp trawl fishery between Charlotte Harbor and the western Florida Keys would reduce sawfish bycatch, and thus mortality, which is in line with recovery plan goals