59 research outputs found
Sex-Specific Growth and Reproductive Dynamics of Red Drum in the Northern Gulf of Mexico
The Red Drum Sciaenops ocellatus stock is heavily targeted in the Gulf of Mexico (GOM) by recreational fishers and supports a small commercial fishery in Mississippi. Despite their popularity, little recent work has been done to describe their life history. In this work, we describe sexâspecific growth and reproductive dynamics of Red Drum collected from the northern GOM from September 2016 through October 2017. We evaluated seven candidate growth models and found that the threeâparameter von Bertalanffy growth function (VBGF) was the best candidate lengthâatâage model. No significant difference in growth between sexes was observed with the threeâparameter VBGF, despite the femaleâspecific curve having a larger mean asymptotic length than the maleâspecific curve. All seven candidate growth models predicted similar mean lengthâatâage estimates, and four of them exhibited significant differences in sexâspecific mean length at age, with females reaching a larger length at age than males after age 5. There was no significant difference between the sexâspecific weightâatâlength relationships. Red Drum are batch spawners that spawn in northern GOM coastal waters during August and September. We estimated 3.7 d between spawns and 10.5 spawning events per female in 2017. Nearly 20% of fish collected during the spawning season were sexually mature but reproductively inactive, indicating the possibility of skipped spawning. The age at 50% maturity was around 3 years (length at 50% maturity = 670 mm TL) in both sexes, but fish were not spawning capable until age 4.5 (703 mm TL) in males and age 5.8 (840 mm TL) in females. Furthermore, elevated gonadosomatic indices were not observed until around age 5â6. The updated life history information presented in this work helps to address current data limitations and provides critical information for future assessments of Red Drum stocks in the northern GOM
A standardized terminology for describing reproductive development in fishes
19 pĂĄginas, 12 figuras, 3 tablas.-- Open access journalAs the number of fish reproduction studies has proliferated, so has the number of gonadal classification schemes
and terms. This has made it difficult for both scientists and resource managers to communicate and for comparisons to
be made among studies.We propose the adoption of a simple, universal terminology for the phases in the reproductive
cycle, which can be applied to all male and female elasmobranch and teleost fishes. These phases were chosen because
they define key milestones in the reproductive cycle; the phases include immature, developing, spawning capable,
regressing, and regenerating. Although the temporal sequence of events during gamete development in each phase
may vary among species, each phase has specific histological and physiological markers and is conceptually universal.
The immature phase can occur only once. The developing phase signals entry into the gonadotropin-dependent stage
of oogenesis and spermatogenesis and ultimately results in gonadal growth. The spawning capable phase includes (1)
those fish with gamete development that is sufficiently advanced to allow for spawning within the current reproductive
cycle and (2) batch-spawning females that show signs of previous spawns (i.e., postovulatory follicle complex) and
that are also capable of additional spawns during the current cycle. Within the spawning capable phase, an actively
spawning subphase is defined that corresponds to hydration and ovulation in females and spermiation in males. The
regressing phase indicates completion of the reproductive cycle and, for many fish, completion of the spawning season.
Fish in the regenerating phase are sexually mature but reproductively inactive. Species-specific histological criteria
or classes can be incorporated within each of the universal phases, allowing for more specific divisions (subphases) while preserving the overall reproductive terminology for comparative purposes. This terminology can easily be
modified for fishes with alternate reproductive strategies, such as hermaphrodites (addition of a transition phase) and
livebearers (addition of a gestation phase)Fish Reproduction and Fisheries (FRESH; European
Cooperation in Science and Technology Action FA0601)
and theWest Palm Beach Fishing Club (Florida) provided funding
for the gonadal histology workshops where this terminology
was developed and refined. Additionally, we thank FRESH for
travel and publication fundsPeer reviewe
Global trends in aquatic animal tracking with acoustic telemetry
Acoustic telemetry (AT) is a rapidly evolving technique used to track the movements of aquatic animals. As the capacity of AT research expands it is important to optimize its relevance to management while still pursuing key ecological questions. A global review of AT literature revealed region-specific research priorities underscoring the breadth of how AT is applied, but collectively demonstrated a lack of management-driven objectives, particularly relating to fisheries, climate change, and protection of species. In addition to the need for more research with direct pertinence to management, AT research should prioritize ongoing efforts to create collaborative opportunities, establish long-term and ecosystem-based monitoring, and utilize technological advancements to bolster aquatic policy and ecological understanding worldwide
Estimating site-specific spawning parameters for a spawning aggregation: an example with spotted seatrout
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Sourceâsink recruitment of red snapper: Connectivity between the Gulf of Mexico and Atlantic Ocean
Geopolitical fishery management boundaries are often misaligned with the ecological population structure of marine species, which presents challenges for assessment and management of these species. Red snapper, Lutjanus campechanus, is an iconic and heavily exploited species in both the US Gulf of Mexico and off the southeastern US Atlantic coast and is managed separately in the two jurisdictions. It is hypothesized that the Atlantic red snapper stock is sustained partially by larval subsidies from the Gulf of Mexico. Here we use a biophysical modeling approach to simulate recruitment of red snapper across the entire Southeastern US region, and quantify rates of larval exchange across management jurisdictions. The biophysical framework simulates realistic red snapper behaviors and traits with respect to spatial distribution and timing of spawning, larval vertical migration and pelagic larval duration, and settlement habitat. Our results suggest that areas of the West Florida Shelf south of Tampa Bay are important sources of larvae for the Atlantic population, supplying as much as one third of the recruitment during some years. Yet, contributions of Gulfâspawned red snapper to the Atlantic stock are highly dynamic given large variability in spatial and temporal patterns of red snapper recovery in each region. As such, effective management of the Gulf of Mexico red snapper stock, particularly the spawning population in southwest Florida, may have important consequences for the sustainable harvest of red snapper off the Atlantic coast
Reproduction features of the non-native Siganus luridus (Teleostei, Siganidae) during early colonization at Linosa (Sicily Strait, Mediterranean Sea)
Reproductive features of the non-native Siganus luridus (Teleostei, Siganidae) during early colonization at Linosa Island (Sicily Strait, Mediterranean Sea)
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