Growth, mortality, and movement of cobia (Rachycentron canadum)

Abstract

Abstract-We describe the lengthat-age relationship of cobia (Rachycentron canadum) with the use of 3 nonlinear models, and examine both the movement patterns of cobia in the Gulf of Mexico and South Atlantic Ocean and the instantaneous total mortality rate (Z, per year) from tag-recovery models with data from the Sport Fish Tag 0.52-0.61]) was greater than that reported for cobia elsewhere. Movements were reported between the Gulf of Mexico and the South Atlantic Ocean and a statistically significant seasonal trend in recaptures was observed, both of which suggest that cobia inhabit the Florida Keys during the winter and the northcentral Gulf of Mexico during the summer. The most supported tag-recovery model included time-invariant survivorship and time-dependent recovery probability and the estimated Z was 0.59/year (95% CI: 0.55-0.63). This study provides a summary of a long-term cobia tagging program and information for future management of this species.

Evaluation of the stock structure of cobia (Rachycentron canadum) in the southeastern United States by using dart-tag and genetics data

“…Additionally, cobia fitted with acoustic transmitters in South Carolina and Georgia were completely absent from detection in coastal receiver arrays in winter (Young et al 9 ), indicating movement into other areas (i.e., deeper water). There is strong evidence that some cobia use the areas along the east coast of Florida and the Florida Keys as overwintering locations before undertaking a seasonal migration into the GOM during spring and summer, as also reported by Dippold et al (2017). To a lesser extent, a similar migration occurs between central and north Florida to the north as described above.…”

“…Life-history characteristics differ between cobia from the GOM and those from the western North Atlantic Ocean, with a faster growth rate in the GOM and a greater maximum age in the Atlantic Ocean (Burns et al 1 ). In the GOM, cobia undertake seasonal migrations from overwintering grounds in South Florida to spawning grounds in the northern GOM during spring and summer (Burns and Neidig 2 ; Ditty and Shaw, 1992;Biesiot et al, 1994;Franks and Brown-Peterson, 2002;Dippold et al, 2017), although some cobia may migrate from deeper offshore overwintering grounds to coastal areas as well (Hendon and Franks 3 ). In the western North Atlantic Ocean, cobia enter high-salinity estuaries as well as nearshore locations in Georgia, South Carolina, North Carolina, and Virginia as water temperatures approach 20°C (Richards, 1967;Smith, 1995;Lefebvre and Denson, 2012).…”

“…Preliminary genetic and tag-capture analyses of cobia stock structure in the southeastern United States conducted in preparation for the 2012 benchmark stock assessment (Perkinson and Denson 4 ; Darden 5 ) cast doubt on the accepted stock boundary in the Florida Keys. Recently, Dippold et al (2017) examined cobia migratory patterns by using tag-recapture data; however, the study focused primarily on 5 zones within the GOM. All regions north of the Florida Keys were combined into a single zone, making a thorough evaluation of the stock boundary delineation between the GOM and Atlantic Ocean stocks difficult.…”

“…Although genetic structure and movements of fish between locations in the GOM to the Atlantic Ocean were evaluated, specific movements of fish solely within the GOM were beyond the scope of this paper, resulting in the entire GOM from Marco Island to the Texas-Mexico border being assigned a single zone. Dippold et al (2017) provide a thorough analysis of cobia movements within the GOM. Analyses of movement between zones as well as recaptures within a zone were largely qualitative and focused on identifying seasonal trends and broad patterns in movement that indicate potential breaks in biological stocks.…”

dl-Methionine supplementation in a low-fishmeal diet affects the TOR/S6K pathway by stimulating ASCT2 amino acid transporter and insulin-like growth factor-I in the dorsal muscle of juvenile cobia (Rachycentron canadum)

“…An economically important carnivorous marine fish, cobia, is globally distributed. It supports recreational and commercial fisheries in the Gulf of Mexico and US Atlantic Ocean and has been widely reared in southern China (33)(34)(35) . Although the dietary Met requirements of cobia have been reported (35,36) , no information is available on how an optimal Met diet affects growth, regulates key AA transporter genes and affects protein metabolism.…”