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In this study, the authors describe a process that consistently identified sex based on differences in the length and characteristics of the urogenital papilla septum of Etelis carbunculus, a deep-water snapper (Lutjanidae, Etelinae). These characteristics, regardless of fish size, were found to be accurate for 96% of 157 specimens evaluated. The application of this external sex determination technique expedites the collection of sex-specific data and may perform well for other morphologically similar lutjanid snappers. The non-invasive method also minimizes damage to the fish, thereby allowing either its return to the ocean or landing as a valuable whole fish.

Deep-water snapper fisheries in the Mariana Archipelago are important commercial, recreational and subsistence fisheries. Pristipomoides zonatus, one of the top four deep-water snapper species harvested in Guam, lacked life-history information. To fill this gap, a comprehensive life-history assessment for P. zonatus, which included age, growth, mortality and reproduction, was conducted in Guam. The size range of P. zonatus sampled for life history was from 11.5 cm to 40.4 cm (fork length), with ages ranging from 0.5 to 30 years. Von Bertalanffy growth model-combined sex parameters were L∞ = 36.91 cm and K = 0.29. Males obtained a larger average size and a larger asymptotic size (+3.03 cm) than did females. Pristipomoides zonatus matures at a small size and age (L50 ≤ 24.0 cm and A50 ≤ 2.1 years) relative to their maximum size (40.4 cm) and age (30 years). Additionally, P. zonatus has a long spawning season and a short spawning interval, suggesting high reproductive output. Our results expand knowledge on Pristipomoides life history (fast early growth, moderately long-lived, high productivity), providing the necessary information for the management of P. zonatus in Guam.

The paucity of species-specific biological information for most exploited Indo-Pacific deepwa¬ter snappers (Lutjanidae) limits stock assessment options and management strategies. To improve stock assessments, age-based demographics were esti¬mated for 2 deepwater snapper species, the goldeneye jobfish (Pristipomoides flavipinnis) in the Samoa Archipelago and the goldflag jobfish (P. auricilla) in the Mariana Archipelago. Each archi¬pelago has locations where fishing had not occurred for at least 30 years, pro¬viding a rare opportunity to examine the effects of exploitation on the age and size compositions, growth, and mortal¬ity of these species. Overall, age-based data reveal a greater effect of fishing pressure than those based on size. This difference highlights concerns with size-based analyses; when species have protracted asymptotic growth trajecto¬ries, the resulting fishing impacts may not be readily apparent in size-based analyses because size and age become decoupled. This decoupling also con¬founds comparisons of growth among areas with different exploitation levels. Mortality estimates derived from an age-based catch curve for the unfished areas (where total mortality equals natural mortality) were comparable to those produced by using a maximum-age-based natural mortality estimator. The comparison of these methods indi¬cates that the age-based natural mor¬tality estimator is suitable for use in deepwater snapper stock assessments when direct measures of natural mor¬tality are unavailable.

Hawaiian grouper (Hyporthodus quernus) is endemic to the Hawaiian Islands and is regionally important, yet little is known about its life history. This large species is managed within the Deep 7 bottomfish complex, which includes six snapper species that are assumed to have similar life history traits. Previous age estimates were not validated and suggested a maximum age of 34 years. To evaluate the preliminary study and provide a valid basis for life history parameters, we aged otoliths using bomb radiocarbon (14C) dating. Measured 14C values provided ages for smallest to largest fish that differed from the original study. The fundamental information provided here when evaluating Hawaiian grouper conservation status is longevity (valid to 50 years and estimated to 76 years) — no male sampled was ∞ = 95.8 cm TL) should be used to improve future management and conservation assessments.

Knowledge of both the life history characteristics and catch and effort statistics of exploited deep-water fishes such as snappers and groupers is typically limited. This contributes to increased uncertainty in stock assessments and, depending on the diligence in governance, is more likely to result in either highly conservative or unsustainable management arrangements. Developments, challenges and advances in the methods for obtaining life history data for these species were discussed at a workshop in May 2015. The key points raised included nascent methods for otolith sectioning and interpretation, the need for standardised international ageing protocols and the issues and challenges in characterising reproductive maturation, including during non-spawning months due to resource limitations. Strategic research directions are identified to address knowledge gaps and thus better inform fisheries management.

In this study, seasonal and annual variability in the use of estuarine and ocean beaches by young-of-the-year bluefish, Pomatomus saltatrix, was evaluated by indices of abundance in coastal areas of southern New Jersey (1998–2000). Biological and physical factors measured at specific sites were correlated with bluefish abundance to determine the mechanisms underlying habitat selection. In addition, integrative and discrete indicators of bluefish growth were used to examine spatio-temporal dynamics in habitat quality and its effect on habitat selection by multiple cohorts of bluefish. Intra-annual recruitment to coastal areas of southern New Jersey was episodic, and resulted from the ingress of spring-spawned bluefish (hatch-date ∼April) to estuarine beaches in late May to early June, followed by the recruitment of summer-spawned fish (hatch-date ∼early July) to ocean beaches from July to October. Bluefish utilized estuarine and ocean beaches in a facultative manner that was responsive to dynamics in prey composition and temperature conditions. The recruitment and residency of bluefish in the estuary (1998–1999) and ocean beaches (1998), for example, was coincidental with the presence of the Atlantic silverside Menidia menidia and bay anchovy Anchoa mitchilli, the principal prey species for bluefish occupying these respective habitat-types. Bluefish abundance in the estuary (2000) and ocean beaches (1999–2000) was also correlated with water temperature, with the greatest catches of juveniles coinciding with their optimal growth temperature (24 °C). Bluefish growth, estimated as the slope of age–length relationships and daily specific growth rates, equaled 1.27–2.63 mm fork length (FL) d−1 and 3.8–8.7% body length increase d−1, respectively. The growth of sagittal otoliths was also used as a proxy for changes in bluefish size during and shortly before their time of capture. Accordingly, otolith growth rates of summer-spawned bluefish were greater at ocean beaches relative to the estuary and were explained by the more suitable temperature conditions found at ocean beaches during the mid- to late summer. Notwithstanding the fast growth of oceanic summer-spawned bluefish, individuals spawned in the spring were still larger in absolute body size at the end of the summer growing season (∼240 and 50–200 mm FL for spring- and summer-spawned bluefish, respectively). The size discrepancy between spring- and summer-spawned bluefish at the onset of autumn migrations and during overwintering periods may account for the differential recruitment success of the respective cohorts.