Results

Pronotogrammus martinicensis

         In total 1,278 specimens of P. martinicensis were collected for study (Table 1). Study specimens ranged from 31-143 mm SL and 1-90 g total weight (TW) (Table 1, Figure 3). Ages were determined for 667 P. martinicensis.  Reproductive biology of the species was described from 318 histological samples. The differing sample sizes are a result of the differing preservation methods used for gonad histology versus otolith aging.

         Sagittal otoliths from P. martinicensis were easily read whole (Figure 4). Opaque rings on P. martinicensis otoliths were confirmed as annuli with a marginal increment analysis (Figure 5). Although there is a drop in the mean marginal increment distance during the month of August, the limited sample (n=3) from this month was collected from the Madison-Swanson Reserve, which displayed unique P. martinicensis growth characteristics (i.e., higher growth rate) compared to the other NEGOM populations sampled. In addition, none of these individuals contained an annulus on the margin (newly forming ring), indicating that rings are indeed deposited once per year.

         Age estimates for P. martinicensis ranged from age-0 to age-IX (Figure 6). The modal age of P. martinicensis collected varied somewhat from reef to reef.  Scamp Reef and Roughtongue Reef populations have a mode at age-IV, while samples from all other reefs examined exhibited a mode of age-III. Growth was rapid during the first year and the majority of somatic growth was completed by age-IV (Figure 7). Annual survival of P. martinicensis age-IV and older was 27% for all reefs combined.

         Pronotogrammus martinicensis from the northeastern Gulf of Mexico exhibited spatial differences in growth rate and mean size-at-age (Figure 7). The mean size-at-age of P. martinicensis from different study reefs varied greatly. Mean size-at-age was most similar among samples from reefs west of DeSoto Canyon, but differed substantially east of DeSoto Canyon. The largest, fastest growing individuals were found in the Madison-Swanson Reserve area while the smallest, slowest growing individuals were from the population inhabiting the Alabama Alps Reef (Figure 7, Figure 8). Growth differences were detectable only in specimens age-II and older.  The mean size of age-IV P. martinicensis from the Madison-Swanson Reserve was unique among the reefs examined (Figure 8).   The sizes of age-IV fish at Catspaw Reef, Porgy Reef, and Yellowtail Reef were not different from each other, but they were larger than P. martinicensis from the Alabama Alps, Roughtongue Reef, and Scamp Reef.

         Pronotogrammus martinicensis is a protogynous hermaphrodite. The size and age distributions for females were smaller/younger than those of transitional samples, which were smaller/younger than males (Figure 9). Most females aged were age-I or younger while male P. martinicensis tended to be age-II or older. Female P. martinicensis collected ranged from 31 to 106 mm SL (Figure 9) and spawn during winter and spring months (February through July) (Table 3). Female reproductive samples were unavailable for the months of January, September, and November. During May the frequency of spawning females was declining; most female ovaries were in a state of regression with atretic bodies prevalent throughout the gonad. No active females were collected between August and January. Females mature in their first year and were reproductively active for all age-classes collected (age-0 to age-IV). Spatial variations in the reproductive biology of P. martinicensis were not examined as a result of limited sample sizes.

         Batch fecundity of P. martinicensis ranged from 149-394 oocytes/spawning event. Females with hydrated oocytes (n=3) ranged in size and age from 55 to 62 mm SL and age-I to age-II. Hydrated females were collected during the months of March and May (Table 3), at which time spawning by some females occurred daily, as was indicated by the coexistence of POFs and hydrated oocytes in the ovary (Figure 10). A single female was also collected during March containing POFs, but oocytes were not in final oocyte maturation (i.e., the individual spawned within 24 hours, however spawning was not imminent that day).  No relationship was found between number of hydrated oocytes and either standard length or somatic weight, presumably due to low sample size.

         The mean size of transitional P. martinicensis collected was 85 mm SL and ranged from 71-104 mm SL (Figure 9). Transitional P. martinicensis (n=2) aged were age-II. Transitional specimens were collected during the months of March, May, June, and August. The development of seminiferous tissue initiated on the periphery of the gonad and moved inwards. Temporally the mean size at sexual transition of our samples was not different than that described by Coleman (1981).

         The mean size of male P. martinicensis collected in the NEGOM was 100 mm SL and ranged from 65-143 mm SL (Figure 9). Males were found as young as age-I and had a mode of age-III.  All P. martinicensis older than age-IV examined were found to be males.  Tailed sperm were present in all male P. martinicensis examined and no trend between month and testicular development was detected.  No evidence of primary males was detected (i.e., a lumen was evident in all males) (Figure 10).

Hemanthias vivanus

         The largest H. vivanus specimens collected from NEGOM reefs were generally smaller the largest specimens of P. martinicensis.  Standard lengths and weights ranged between 31-107 mm and 0.5-33.0 g, respectively (Figure 11). Ages were recorded for 211 individuals and reproductive stage was assessed for 174 individuals.  The differing sample sizes are a result of the differing preservation methods used for gonad histology versus otolith aging.

         Hemanthias vivanus have relatively large sagittal otoliths, which were easily aged whole (Figure 12). Individual H. vivanus were sampled from multiple age-classes with the oldest fish estimated to be age-VIII (Figure 13). The mean age-class of H. vivanus collected were in their third year of growth (age-II), while the mode was in their second year of growth (age-I). Young-of-the-year (YOY= age-0) were under-represented as a result of sampling bias from the use of hook and line gear.  To account for this under-representation, annual survival estimates were conducted excluding age-0 individuals. Annual survival for H. vivanus age-I and older in the NEGOM was estimated to be 48%.

         Standard lengths of H. vivanus used for age and growth analysis ranged from 50 to 107 mm.  Mean SL increased with number of rings on otoliths until age-II when growth slowed (Figure 14), indicating that the majority of somatic growth occurred during the first two years.  The mean SL of age-0 and age-I was most likely over-estimated as a result of sampling bias towards larger specimens.

         The smallest and youngest individuals collected were females or transitionals, except for two males, 46 and 62 mm SL. Larger specimens (>77 mm) were entirely male (Figure 15). No H. vivanus gonads were observed containing simultaneously active male and female reproductive tissue, indicating that the species is a protogynous and not simultaneous hermaphrodite.  Female H. vivanus may mature as small as 47 mm SL; no females were observed larger than 76 mm SL. Spawning occurs during the winter and spring months, as POFs were observed during the months of March and May (Table 3; Figure 16). Standard lengths of female and transitional H. vivanus indicate that all females examined during this study were age-0 (Figure 14). This indicates that H. vivanus spend up to one year as a female after which sexual transformation ensues. No females undergoing final oocyte maturation or hydration were collected; as a result no fecundity estimates were generated.

         Gonad transformation begins on the periphery of the ovary and progressively moves inward. The smallest and largest transitional H. vivanus observed were 49 mm and 77 mm SL, respectively (mean 67 mm SL) (Figure 15). Otoliths were unavailable for transitional H. vivanus, however, age at length data (Figure 14) suggest that these individuals are age-0.  No evidence of primary males was detected (i.e., a lumen was observed in all males) (Figure 16). The mean size at sexual transition for our samples was not different than that described by Hastings (1981).

         Sexual dimorphism was evident in Hemanthias vivanus populations.  As individuals grew and underwent sexual transformation the fourth dorsal filament (4D) elongated (Figure 17).   The 4D length in female H. vivanus ranged from 6-30% of the SL (mean 16%). Transitional and male H. vivanus 4D lengths ranged from 8-52% SL (mean 29%) and 11-74% (mean 49%) of the fishes SL, respectively.

Serranus phoebe

         Serranus phoebe is the largest of the three serranid study species. Individuals collected for the present study (n=392) (Table 1) ranged in size from 43-168 mm SL and 2.5-143.4 g TW (Figure 18). Age and growth analysis was completed using age estimates from 290 individuals, and reproductive data were generated from 206 histological samples.  The differing sample sizes are a result of the differing preservation methods used for gonad histology versus otolith aging.

         Sagittal otoliths from S. phoebe were easily read when viewed whole (Figure 19). Multiple age-classes were observed ranging from age-0 to age-V (Figure 20). Serranus phoebe grows rapidly during its first year and maximum size is attained during the fourth year of growth (Figure 21). The modal age of S. phoebe was age-II in our samples, with the population mean in their second year of growth.  However, the modal age estimate from our sample is probably lower than that of the true population due to size-bias from sampling methods. Annual survival of S. phoebe age-II and older was 27%.

         Serranus phoebe is a simultaneous hermaphrodite with un-delimited gonad structure (i.e., male and female tissue is not separated by connective tissue) (Figure 22). The hermaphroditic nature of S. phoebe gonads is readily visible macroscopically.  Testicular material is creamy white and is located on the anterior periphery of the gonad, as well as in lobes protruding into the interior of the gonad.  Ovarian material is yellowish in color, and dominated the posterior two-thirds of the gonad.   Traditional methods for fecundity determination were unsuitable and could not be applied.

         Vitellogenic oocytes were observed in S. phoebe as small as 83 mm SL, indicating that S. phoebe can mature during their first year of life.  Otoliths and gonads were removed from 160 specimens of S. phoebe.  All individuals of S. phoebe age-III and older were reproductively active.

         The presence of hydrated oocytes and/or POFs in histological samples during the months of March, May, August, and October reveals that S. phoebe spawn throughout much of the year. During the months of March and August 96% of S. phoebe in final oocyte maturation contained POFs in their gonads, indicating that S. phoebe spawns daily throughout much of the spawning season.

Chromis enchrysurus

         All Chromis enchrysurus collected for age and growth analysis (n=56) came from the NEGOM (Table 1). These deep-living planktivores are extremely difficult to capture except with Sabiki-type rigs.  Prior to the USGS Pinnacles and NEGOM programs, only a handful of preserved museum specimens were available for study.  Standard lengths of NEGOM sampled C. enchrysurus ranged from 62-90 mm and TW from 12.4-32.3 g (Figure 23). Total weight was not obtainable from all samples due to variability in sample quality (fins and abdominal cavities were occasionally missing). Reproductive data were not taken since all samples were frozen. 

         No ring structure was visible on whole otoliths; therefore, age estimates were derived from sectioned otoliths.  Age estimates from C. enchrysurus sectioned sagittal otolith (Figure 24) ranged from age-I to age-XI (Figure 25). Standard length was not a good indicator of age for our samples. Little variation was seen in the SL of C. enchrysurus, regardless of age, indicating the majority of growth occurs during the first year of life (Figure 26).