Defining a spawning population (spotted seatrout Cynoscion nebulosus) over temporal, spatial, and demographic scales

Abstract

Fish spawning populations are complex and affected by many factors acting over temporal, spatial, and demographic scales. To better understand these factors, we chose to study spotted seatrout Cynoscion nebulosus, which has closed populations over small spatial scales and a periodic life-history pattern. We used experimental gill nets and hook and line, within a spatially and temporally explicit sampling design, to collect 2034 spotted seatrout in lower Tampa Bay, Florida, USA, in 2001 and 2002. Ovarian development was evaluated histologically. Mature females did not all spawn throughout the spawning season, and first-time spawners (Age 1) had the lowest probability of doing so. Two reproductive behaviors were observed: fish moving in the late afternoon or evening to a high-intensity spawning site in an inlet and low-intensity spawning within the estuary. Larger, older female and male spawners were more abundant at the inlet site than at nearby estuarine sites. Both batch fecundity and the percentage of females spawning increased with age and size. Spatialtemporal interactions made it difficult to assess certain aspects of reproduction, such as spawning frequency.

More Than Just a Spawning Location: Examining Fine Scale Space Use of Two Estuarine Fish Species at a Spawning Aggregation Site

“…We aimed to tag an even 1:1 sex ratio for both species. Seatrout sex ratios in the focal system are close to 1:1, and snook sex ratios in Tampa are likely skewed more toward males (1.2:1, Taylor et al, 2000;Lowerre-Barbieri et al, 2009). We used a combination of tag types to allow for at least some of the larger fish implanted with V-13s to be detected for multiple years.…”

Reproductive output traits of the simultaneous hermaphrodite <I>Serranus scriba</I> in the western Mediterranean

“…Ovulation occurs at the diel scale and typically indicates spawning as ovulated eggs in most species remain viable for only a short time period (Lowerre-Barbieri et al 2009). The highest percentage of individuals with indicators that spawning was imminent was observed before sunset.…”

Reproductive strategy and fecundity of meagre <i>Argyrosomus regius</i> Asso, 1801 (Pisces: Sciaenidae): implications for restocking programs

“…However, the vast differences in size that are considered here cast some doubts on the pattern that was observed because reared females presented higher potential fecundities for a given somatic weight than wild females. Size-independent, between-population variability in fecundity has only been reported recently (Lowerre-Barbieri et al 2009), and it has potential effects on population dynamics; therefore, further investigation of this topic is needed.…”