The genus Albula includes marine fish species, commonly called bonefish, that occur in tropical coastal ecosystems worldwide. Their association to nearshore marine environments makes bonefish especially vulnerable to habitat loss and overharvest. Artisanal fisheries often harvest bonefish, although, in certain areas, bonefish support lucrative catch-and-release recreational fisheries. Bonefish are largely understudied compared to other economically significant fish species, and the presence of cryptic species within the Albula genus has further complicated the establishment of conservation measures. In particular, there is no detailed biological information available on bonefish from the Red Sea despite the unregulated harvest of bonefish that occurs there. To facilitate the establishment of management and contribute to the overall knowledge of Albula biology, I assessed the genetic diversity, growth, and seasonal reproduction of bonefish in Saudi Arabia. Based on samples collected from local fish markets and coastal waters, my findings provide the first genetically verified records of A. glossodonta in the Red Sea and A. oligolepis in the northwest Indian Ocean. Moreover, my results indicate a genetically distinct Red Sea population of A. glossodonta that reaches smaller sizes than documented for the species in the Pacific Ocean and exhibits distinct seasonal spawning activity over the winter months. This information enables fishery managers to make informed decisions regarding bonefish size limits and seasonal colures around peak spawning activity. My results may become increasingly relevant as the potential for lucrative recreational fisheries for Albula glossodonta will likely increase with the ambitious Red Sea tourism development plans.

Bonefish (Albula spp.) support an economically important sport fishery, yet little is known regarding the reproductive biology of this genus. Analysis of oocytes histology and sex hormone levels was conducted on wild female bonefish sampled during and outside the spawning season in Grand Bahama, Central Andros, and South Andros, The Bahamas to assess reproductive state. Bonefish are commonly found along shallow water flats, or in pre-spawn aggregations (PSA) during spawning months. 17β-estradiol levels suggest vitellogenic consistency between habitats. However, fish are more reproductively developed at PSA based on the occurrence of larger, more prevalent vitellogenic oocytes and evidence of final maturation. Variability in hormone levels and spawning readiness existed between Grand Bahama and Andros PSAs, suggesting peak spawning may differ by region. Findings from this study will contribute baseline data to the captive bonefish restoration project at Harbor Branch Oceanographic Institute and to the limited ecological data regarding bonefish reproduction. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Relying on field research to complete the life history for certain fish species can be inadequate, but laboratory research can be used to fill these gaps. These gaps exist for Bonefish (Albula spp.), a tropical marine fish and popular sportfish. In this study, aquaculture techniques were applied to Bonefish in a captive setting at Harbor Branch Oceanographic Institute (HBOI) and Cape Eleuthera Institute (CEI) to induce spawning and describe early ontogeny. Photothermal manipulations and hormone injections were used to induce gonad maturation and spawning, which was achieved once at CEI and is the first record of hormone-induced spawning for Bonefish. From that spawn, egg and larval development were recorded and described through 26 hours and 56 hours respectively, representing the first record of these early life stages for Bonefish. This work expands upon what is known about Bonefish reproductive biology and will be useful for management and future captive research. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Florida’s recreational bonefish fishery generates substantial economic benefits to the region; however, the resource has never been adequately assessed to determine standard benchmarks for sustainability. The situation offered a unique opportunity to address unresolved issues in sustainability for a valuable recreational fishery that is almost exclusively catch and release. The goal of this dissertation was three-fold: (1) to develop a comprehensive framework for conducting rigorous stock assessments on recreational catch-and-release fisheries; (2) to apply these methods to the Florida bonefish fishery to compare results against internationally-recognized sustainable fishery benchmarks; and, (3) provide recommendations for longer-term assessment strategies and management efforts. Due to the dearth of available bonefish information, existing literature were synthesized and new quantitative data and models concerning bonefish demographics (i.e. growth, survivorship) and population dynamics were developed. Data for age-and-growth were collected with a focus on both small (< 100 mm FL) and large (>650 mm FL) bonefish which had been under-sampled in previous research. A two-stage growth model was developed that allowed predictions of size-at-age over the complete life history of the species. Evidence from multiple analyses suggested a single species of bonefish in the Florida fishery. A mail survey of bonefish captains (guides) acquired baseline statistics on the south Florida bonefish fishery. Fleet fishing effort is mostly concentrated in the northern Florida Keys (Biscayne Bay to Islamorada) and reflects to some extent bonefish spatial population abundance. The majority of the respondents indicated the stock had declined over the past few decades. A sized-based mortality estimator was used to determine mortality. Changes in current population size from 2003-2010 were determined from a visual survey. Historical stock size was inferred from a relative abundance index from standardized tournament catch rates. Annual trends of the mortality estimates implied a stable population that is not declining which contrasts with the index of abundance and visual survey results. Both the index of abundance and visual survey displayed overall declining trends in recent years. Bonefish movements were determined from anchor tag and acoustic telemetry. Anchor tagging data were analyzed to evaluate movements, stock size structure and mortality. Results revealed no significant relationships between distance moved and days at large or days at large and length at tagging; however, significant individual movements (>100 kilometers) were recorded. Use of acoustic telemetry showed frequent movements around the barrier islands, schooling behavior, and a possible spawning effect with movements to offshore reef habitats. Stock status was addressed with two different classes of assessment models: REEFS, a length-based model which estimated the stock as moderately exploited with the current fishing mortality rate less than the maximum sustainable yield fishing mortality rate; and a “catch-free” age-structured model which indicated a large stock decline over the past 40 years with the stock currently bordering an overfished benchmark. The age-structured model was assumed to be the most robust method because it incorporated the majority of the research data (age and growth, selectivity, mortality, visual survey, CPUE standardization, vessel effort). In conclusion, the stock’s productivity has been significantly reduced over the past 50 years due to fishing, but also degradation of key prey populations, habitats, and water quality, resulting in a current bonefish population that is bordering an overfished state. Recommendations are provided for improving future stock assessments and management approaches. The assessment framework and quantitative methods and models developed here are broadly applicable to bonefish stocks around the world.

Bonefish (Albula spp.) support an economically important catch-and-release recreational fishery, as well as artisanal harvesting, in The Bahamas. Little is known about the large-scale movement patterns of bonefish, yet such information is essential for proper species conservation and management. I used acoustic telemetry to determine large-scale movement patterns of bonefish around Andros, Bahamas, in conjunction with presumed spawning migrations. I conclude that bonefish travel long distances from shallow flats to pre-spawning aggregation sites in proximity to off-shore reef locations. Off-shore movement to deeper reef locations occurs around both new and full moons. This study has also confirmed anecdotal reports that the North Bight is an important spawning migration corridor for bonefish. This information is critical for the protection of bonefish and identifies important habitats (e.g. migration corridors and pre-spawning aggregations) on Andros that warrant protection from coastal degradation or fishing pressures.

Gegenstand der Arbeit war die Untersuchung der Rolle der Schwebegarnele Mysis relicta im pelagischen Nahrungsnetz des Breiten Luzins unter besonderer Berücksichtigung der trophischen Interaktionen zur Kleinen Maräne Coregonus albula. Schwerpunkte waren die Abundanz und räumlich-zeitliche Verteilung von M. relicta, C. albula und dem Zooplankton sowie die trophischen Beziehungen im Pelagial. Im Vergleich zu früheren Studien war M. relicta weiträumiger und mit höherer Dichte im Untersuchungsgebiet verbreitet. Dies war auf die Verbesserung der Wasserqualität zurückzuführen. Ähnliche Verteilungsmuster führten zu starken räumlichen Überlappungen von M. relicta und C. albula. M. relicta konsumierte vorwiegend abundantes Plankton. Es zeigte sich aber auch eine Präferenz für Cladocera. Aus den in vitro ermittelten Ingestionsraten wurde für die Situation im Freiland ein starker Fraßdruck von M. relicta auf das Zooplankton abgeleitet. In Kombination mit einer Überschneidung der Beutespektren führte das zur Nahrungskonkurrenz zwischen M. relicta und C. albula. Andererseits war M. relicta eine wichtige Beute für C. albula und wurde stark positiv selektiert. Die Fettsäuremuster der untersuchten Organismen waren überwiegend durch ihre Nahrung beeinflusst. Die Aufnahme von M. relicta wurde nicht durch das Auftreten spezifischer Fettsäuren bei C. albula nachgewiesen. Grundsätzlich entsprach der Energietransfer im Nahrungsnetz des Breiten Luzins allgemeinen Modellen mit 10 % Transfereffizienz zwischen benachbarten trophischen Ebenen. Im Einzelnen zeigten sich aber auch Abweichungen, die größtenteils auf M. relicta zurückzuführen waren. Durch ihre omnivore Ernährung und als Beute für C. albula schafft M. relicta zusätzliche Verbindungen zwischen den trophischen Ebenen. Insgesamt hat M. relicta einen weitreichenden Einfluss auf die Struktur und den Energietransfer des Nahrungsnetzes im Breiten Luzin, wodurch ihr Vorkommen für das Gewässer von besonderer Bedeutung ist. / The aim of the study was to investigate the role of the opossum shrimp Mysis relicta in the pelagic food web of Lake Breiter Luzin (Germany) with special focus on trophic interactions with European cisco Coregonus albula. Main aspects were the abundance and temporal and spatial distribution of M. relicta, C. albula and zooplankton as well as trophic relationships in the food web. As a result of improved water quality M. relicta showed a wider distribution and enhanced abundances in the study area than earlier investigations suggested. Due to similar diurnal vertical distributions a great spatial overlap was evident for M. relicta and C. albula. M. relicta fed mainly on highly abundant plankton. Besides, an overall preference for cladocerans was detected. By applying estimated in vitro feeding rates to field situations it could be shown that zooplankton was strongly exploited by M. relicta. This high demand combined with similar prey preferences of C. albula led to a strong food competition between M. relicta and C. albula. On the other hand M. relicta formed high amounts in the diet of C. albula and was always positively selected. Fatty acid composition of examined organisms resembled the composition found in their dietary resources. The intake of M. relicta could not be detected by a specific fatty acid composition in C. albula. Considering highest and lowest trophic levels, transfer efficiency in Lake Breiter Luzin fit into general models assuming a transfer of 10 % between neighbouring trophic levels. Transfer between intermediate trophic levels partly differed from this general pattern. This was connected to the existence of M. relicta. Being omnivorous and by providing an important food source for C. albula the mysid established additional links between trophic levels in the food web. In summary, M. relicta is a significant factor in structuring the food web of Lake Breiter Luzin and has profound impact on the entire lake ecosystem.