Daniel J. Pondella

Oil platforms off California are among the most productive marine fish habitats globally

Significance Secondary production is the formation of new animal biomass from growth for all individuals in a given area during some period of time. It can be a powerful tool for evaluating ecosystem function because it incorporates multiple characteristics of a population or community of organisms such as density, body size, growth, and survivorship into a single metric. Here, we find that fish communities living on the complex hardscape habitat created throughout the water column by the structure of oil and gas platforms off California have the highest secondary production per unit area of seafloor of any marine ecosystem for which similar estimates exist. Secondary (i.e., heterotrophic or animal) production is a main pathway of energy flow through an ecosystem as it makes energy available to consumers, including humans. Its estimation can play a valuable role in the examination of linkages between ecosystem functions and services. We found that oil and gas platforms off the coast of California have the highest secondary fish production per unit area of seafloor of any marine habitat that has been studied, about an order of magnitude higher than fish communities from other marine ecosystems. Most previous estimates have come from estuarine environments, generally regarded as one of the most productive ecosystems globally. High rates of fish production on these platforms ultimately result from high levels of recruitment and the subsequent growth of primarily rockfish (genus Sebastes) larvae and pelagic juveniles to the substantial amount of complex hardscape habitat created by the platform structure distributed throughout the water column. The platforms have a high ratio of structural surface area to seafloor surface area, resulting in large amounts of habitat for juvenile and adult demersal fishes over a relatively small footprint of seafloor. Understanding the biological implications of these structures will inform policy related to the decommissioning of existing (e.g., oil and gas platforms) and implementation of emerging (e.g., wind, marine hydrokinetic) energy technologies.

Comparing volunteer and professionally collected monitoring data from the rocky subtidal reefs of Southern California, USA

Volunteer-based citizen monitoring has increasingly become part of the natural resources monitoring framework, but it is often unclear whether the data quality from these programs is sufficient for integration with traditional efforts conducted by professional scientists. At present, the biological and physical characteristics of California’s rocky reef kelp forests are concurrently monitored by two such groups, using similar methodologies—underwater visual census (UVC) of fish, benthic invertebrates, and reef habitat, though the volunteer group limits their sampling to transects close to the reef surface and they use a more constrained list of species for enumeration and measurement. Here, we compared the data collected from 13 reefs that were sampled by both programs in 2008. These groups described relatively similar fish communities, total fish abundance and abundance of the dominant fish species but there were some differences in the measured size distributions of the dominant fish species. Descriptions of the benthic invertebrate community were also similar, though there were some differences in relative abundance that may have resulted from the less detailed subsampling protocols used by the volunteers. The biggest difference was in characterization of the physical habitat of the reefs, which appeared to result from selection bias of transect path by the volunteer program towards more complex structured sections of a reef. Changes to address these differences are relatively simple to implement and if so, offer the promise of better integration of the trained volunteer monitoring with that of professional monitoring groups.

The phylogeny of Paralabrax (Perciformes: Serranidae) and allied taxa inferred from partial 16S and 12S mitochondrial ribosomal DNA sequences

Partial sequences of 16S and 12S mitochondrial ribosomal DNA were used to examine the phylogenetic relationships of the primarily eastern Pacific genus Paralabrax (Perciformes: Serranidae) and allied taxa. Paralabrax is considered a basal serranine, which is itself considered the basal subfamily in the Serranidae. Multiple serranines reported closely related to Paralabrax from the genera Serranus, Hypoplectrus, Cratinus, and Centropristis were used as outgroups. Species from the remaining two subfamilies, Epinephilinae and Anthiinae, of the Serranidae were also used in the analyses. The tree of the Serranidae was rooted with the families Polyprionidae and Priacanthidae. Paralabrax, the Serranidae, and the Serraninae were monophyletic in this study. Serranus was found to be paraphyletic. Centropristis, formerly considered the sister taxon to Paralabrax, was not closely related in these analyses. Cratinus agassizii, a monotypic genus from the eastern Pacific, was found to be the sister taxon to Paralabrax. There is greater resolution for intergeneric and subfamily relations than interspecific relationships. A single most parsimonious tree for the interspecific relationships of Paralabrax and allied taxa is proposed. This proposed molecular phylogeny is consistent with known biogeographic processes in the eastern Pacific.

Development and application of genomic tools to the restoration of green abalone in southern California

Due to severe declines in abundance throughout southern California, the green abalone (Haliotis fulgens Philippi 1845) became protected under a state-sponsored fishery moratorium in 1997 and was declared a NOAA NMFS Species of Concern in 2004. Recently, H. fulgens was chosen for possible stock restoration via translocation of wild adults to depleted habitat and supplementation through releasing cultured individuals. Before a management plan could be developed, however, an understanding of the species’ natural population genetic structure was needed. We used a genomic technique called restriction site associated DNA sequencing (RADSeq) to address the issue. RADSeq enabled discovery of 1,209 single nucleotide polymorphisms theoretically spread genome-wide in H. fulgens. Analyses suggested the species may be panmictic throughout our sampled range, with an effective population size (Ne) of 1,100–3,600. Hence, limitations to management, such as requiring local broodstock and restricting translocation potential, might be unnecessary. Sites with larger populations may be suitable sources for restoration of depleted sites (e.g. the Palos Verdes Peninsula), although the extent of local adaptation remains unknown. Despite this potential for restoration, results gathered on a sample of cultured H. fulgens illustrated how quickly genetic diversity can be lost through captive breeding. To help mitigate a drop in Ne due to hatchery supplementation, we recommend collection and replacement of ≥100 wild abalone per generation for broodstock and close management of the proportion of cultured individuals in the wild. Successful implementation will depend on operational capacity and the resilience of the source populations to broodstock collection.

The Fish Assemblages Inside and Outside of a Temperate Marine Reserve in Southern California

Abstract The purpose of this investigation was to evaluate the effect of a small marine reserve (established 1988) on a temperate rocky reef fish assemblage at Santa Catalina Island, California. Fish surveys on SCUBA were conducted at two reserve and two non-reserve sites from October 2002 to January 2004. Sites were similar in fish density, species richness and biomass of the entire fish assemblage. However, the adult densities of two important fishery species, California sheep-head (Semicossyphus pulcher; 7.6 ±0.5 and 5.5 ±0.4/100 m2 inside versus outside) and kelp bass (Paralabrax clathratus; 3.6 ±0.4 and 2.9 ±0.4 inside versus outside), were significantly higher within the reserve. The reserve appears to be effective in increasing density and biomass of two impacted species that were readily observed and surveyed on SCUBA.

Kelp forest habitat restoration has the potential to increase sea urchin gonad biomass

When taking an ecosystem-based approach to marine resource management, managers may be able to implement a combination of management tools in order to mitigate the socioeconomic impacts of implementing any one in isolation, while providing greater overall ecological benefits. The harvest of Strongylocentrotus franciscanus (red sea urchin) for their gonads is one of the most important commercial fisheries in California. However, in some locations, high densities of the unfished Strongylocentrotus purpuratus (purple sea urchin) can clear expanses of kelp forest resulting in “urchin barrens.” The lack of macroalgal food resources can result in reduced gonad production, making S. franciscanus within barrens less valuable to a fishery. We investigated the potential of kelp forest habitat restoration, which may be achievable primarily by removing S. purpuratus from barrens, to positively impact the local S. franciscanus fishery and offset the losses in fishing grounds within recently established MPAs in our study area. Generalized linear modeling of the relationship between gonad weight and length (test diameter) demonstrated clear size-specific differences in gonad production between urchins collected in barrens and kelp forests. These relationships varied over time, with the maximum observed mean gonad biomass at length being 484% greater in kelp forest than barren habitat for S. franciscanus just above the legal size limit. The variability in S. franciscanus density (5.2 times greater in urchin barrens), size structure (mean test diameters were approximately 50% greater in kelp forest) and gonad production were then incorporated using Monte Carlo simulations. Results indicated that restoration could potentially result in an 864% increase in S. franciscanus gonad biomass available to the fishery, and a 132% increase in reproductive potential per unit area of urchin barren restored to kelp forest. If all 36 ha of urchin barren habitat mapped outside of the new MPAs in the study area were restored, the increase in gonad biomass available to the fishery could potentially offset 52% of which is now protected within the 109 ha of rocky reef in the new MPAs. Kelp restoration has the potential to play a valuable role as one of many integrated tools in an ecosystem-based management approach.

Life History and Courtship Behavior of Black Perch, Embiotoca jacksoni (Teleostomi: Embiotocidae), from Southern California

ABSTRACT The black perch, Embiotoca jacksoni Agassiz, 1853, is a common reef fish associated with nearshore marine habitats of California, with the majority of the population occurring within the Southern California Bight. Black perch were collected throughout southern California from Santa Barbara to Carlsbad, including Santa Catalina Island, to determine their physical characteristics, growth, sex ratio, periodicity of reproduction, and length of gestation. Courtship observations were conducted using scuba along the King Harbor Breakwater in Redondo Beach, California, from January 2004 to December 2005 to verify periodicity of courting and associated reproductive behaviors. Specimens captured ranged from 75 to 220 mm standard length and from 18 to 487 g in total body weight. Seven age-classes were determined by otolith aging, with the growth rate tapering off after age-class one. Seventy percent of the individuals captured were from age-classes one to three. Growth rates did not differ between sexes. Mean monthly gonosomatic indexes for males peaked from July to November, with the highest mean occurring in October. Gestating females were found from December to May, with youngest gestating females being in age-class one. Courtship behaviors were observed within aggregations and in pairs from July to November, with males being the primary aggressors. Courtship postures occurred along the base of the reef, with pairs departing into caves for copulation. This study suggests that the black perch population within the Southern California Bight has different life history characteristics and reproductive timing than those in northern California.

Demographic Parameters of Yellowfin Croaker, Umbrina roncador (Perciformes: Sciaenidae), from the Southern California Bight.

ABSTRACT The yellowfin croaker, Umbrina roncador Jordan & Gilbert, 1882, is a common nearshore and surf-zone species in the southern California bight. Age was determined for individuals (n = 1,209) using annual increments in otoliths, and size at age was modeled using the von Bertalanffy growth curve (L∞ = 307.754 mm, k = 0.278 yr−1, t0 = −0.995 yr; maximum age = 15 yr). Females (L∞= 313.173 mm, k = 0.307 yr−1, t0 = −0.771 yr) grew significantly faster and larger than males (L∞= 298.886, k = 0.269 yr−1, t0 = −1.072 yr). Age and growth modeling based upon otolith length (OL) and width (OW) measurements were assessed and were consistent with body measurements. Males and females were found in all size classes and in an overall 51.49 ratio that was not significantly different from a 50% sex ratio, suggesting that these fish are gonochores. Fish were reproductive during summer months, with gonadosomatic indices (females, 5.65%; males, 5.51%) consistent with group-spawning fishes. Data from two separate monitoring programs indicated that yellowfin croaker catch-per-unit-effort (CPUE) fluctuated appreciably from 1992 to 2006 on both spatial and temporal scales. CPUE also declined significantly in the latter years of these programs. Based on samples collected between 2003 and 2004, an estimate of overall annual total mortality was A = 0.4492, and instantaneous coefficient of total mortality was estimated at Z = 0.5964. Recruitment year classes were back calculated using annual survivorship. Year class strength was variable and declined significantly by the end of this study. Considering the high temporal and spatial variation in estimates of abundance and recruitment, coupled with the likelihood that these fish employ a probable group-spawning reproductive behavior, we recommend a cautious approach for the future management of this species.

Demographic Parameters of Golden Spotted Rock Bass Paralabrax auroguttatus from the Northern Gulf of California

Abstract The sex ratios, growth, and mortality of the golden spotted rock bass Paralabrax auroguttatus (Serranidae) were determined for populations from Islas Encantadas and Bahia de los Angeles in the Gulf of California. Specimens ranged from 137 to 479 mm standard length and from 135 to 3,100 g. Sagittal otoliths were used to determine age. A von Bertalanffy model of growth for both populations combined was estimated as Lt = 474.4·(1 − e −0.115( t + 2.093)), where Lt is fish length at age t. This model is comparable to those for other rock basses. The relationship between length and weight (W) followed the power function W = 0.00002·L 3.0797 (r 2 = 0.96) with no difference between males and females. The mortality rate was estimated as 49% per year for fish of age 5 and older. In our Bahia de los Angeles samples, the sex ratio was significantly skewed, with more males than females. The mean size of females was significantly smaller at Bahia de los Angeles than in Islas Encantadas. Examination of the sex ...

Life history, ecology, and long-term demographics of queenfish

Abstract Queenfish Seriphus politus were collected at coastal power plants from San Clemente to Ventura, California. Power functions best described relations between otolith length, width, or weight and either standard length (SL) or total body weight. The length–weight relationship was described by the following equation: weight = 10−5 × SL3.09. Individuals were aged to 12 years by using sagittal otolith sections. Females grew at a significantly faster rate than males. Both sexes reached 50% maturity by 100 mm SL, or shortly after age 1. The total annual instantaneous mortality coefficient was estimated at 0.42. Catalina Harbor (on the windward side of Santa Catalina Island) and Ventura were the most populous sites based on gill-net catch per unit effort from 1995 to 2006. Juvenile and adult queenfish populations have declined since 1980 in a significant relationship with nearshore plankton biomass. Larval queenfish densities recorded in King Harbor (Redondo Beach) have declined since 1987. Long-term recruitment estimates indicated peak recruitment prior to 1976, with three subsequent downward baseline shifts.