Marine Artificial Reef Research and Development: Integrating Fisheries Management Objectives

<em>Abstract</em>.—Reef-fish assemblage structure was compared among multiple artificial and geologic (i.e., naturally occurring hard bottom) habitats in the northeastern Gulf of Mexico during 2014–2016 as part of a larger fishery-independent survey. Baited remote underwater video systems equipped with stereo cameras were deployed (<em>n </em>= 348) on 11 habitat types, classified through interpretation of side-scan sonar imagery. In the video samples, 11,801 fish were enumerated. Nonparametric analysis of reef-fish assemblages detected four clusters related to habitat; assemblages associated with geologic habitats were distinct, whereas the remaining three clusters represented groupings of artificial habitats of different size, scale, and complexity. While many species, including Vermilion Snapper <em>Rhomboplites aurorubens </em>and Red Snapper <em>Lutjanus campechanus</em>, were observed in greater numbers on artificial reef habitats, most species were observed in all habitats sampled. Among artificial reef habitats, the habitat cluster consisting of unidentified depressions, unidentified artificial reefs, construction materials, and reef modules was similar to geologic habitats in supporting larger individuals, specifically Gray Triggerfish <em>Balistes capriscus </em>and Red Snapper. In contrast, the habitat cluster consisting of smaller, generally solitary chicken-transport cages was inhabited by smaller individuals, including smaller Red Snapper. Although geologic reefs are the predominant reef habitat throughout much of the eastern Gulf, artificial reefs are important locally, especially in the Florida Panhandle. Accordingly, continued incorporation of artificial reef habitats within large-scale fishery-independent monitoring efforts is critical to the accurate assessment of the status of reef-fish stocks on broad spatial scales.

<em>Abstract</em>.—Visual census scuba surveys (<em>n </em>= 87) were used to compare fish assemblages among three artificial reef types: big reefs (e.g., ships), tank reefs (i.e., U.S. Army tanks) and small reefs (e.g., metal cages and concrete pyramids), over three locations on the continental shelf (inner shelf, 18–26-m depths; mid-shelf, 26–34-m depths; outer shelf, 34–41-m depths) from April 20, 2012 to November 30, 2015 in the northeast Gulf of Mexico. These surveys identified 66 fish taxa (lowest taxon: 58 species, five genera, three families), and 65 taxa were used in community comparisons. Artificial reefs were dominated by Red Snapper <em>Lutjanus campechanus </em>(35.3% of total fish observed), Tomtate <em>Haemulon aurolineatum </em>(22.4%), Vermilion Snapper <em>Rhomboplites aurorubens </em>(19.5%), Atlantic Spadefish <em>Chaetodipterus faber </em>(7.0%), Greater Amberjack <em>Seriola dumerili </em>(3.0%), and Gray Triggerfish <em>Balistes capriscus </em>(1.8%). These six most abundant species comprised 89% of the total number of individuals observed. Red Snapper and Greater Amberjack mean sizes (total length mm) were larger at big reefs, Vermilion Snapper and Atlantic Spadefish were larger at tank reefs, and Tomtates were larger at small reefs. Red Snapper, Atlantic Spadefish, and Greater Amberjacks were larger at reefs on the outer shelf, and Red Snapper, Tomtates, Vermilion Snapper, Atlantic Spadefish and Greater Amberjacks were larger in the spring. Richness and Shannon–Wiener diversity indices were higher on big reefs and tank reefs compared to small reefs. Evenness, richness, and Shannon–Wiener diversity were lower in winter compared to other seasons. Fish assemblages, based on Bray–Curtis similarities, were different among reef type, location, and season, but no interactions effects were identified. In the present study, fish assemblages on big reefs were more similar to assemblages on tank reefs in comparison to small reefs. The larger size, longer life span, and relative stability of the big reefs and tank reefs were the reef attributes most likely responsible for these assemblage associations. Similarly, more stable conditions at deeper depths (less affected by tropical storms) and proximity to deepwater reef fish communities (e.g., pinnacle reefs) most likely influenced the increased assemblage diversity on the artificial reefs at outer-shelf locations. Diversities and densities were highest during the fall. This was most likely due to increased recruitment of tropical species and new age-0 recruits that were spawned during the same year. The attributes of all artificial reefs are not identical; consequently, it is important for managers to consider how reef type, shelf location, and season affect each species’ affinity and association with artificial reefs.


<em>Abstract.</em>—Red snapper, <em>Lutjanus campechanus</em>, (<em>n </em>= 4,317) were captured and tagged at 14 experimental artificial reefs of two designs during quarterly research cruises (<em>n </em>= 17) off coastal Alabama between January 1999 and October 2002. Six-hundred and twenty nine recaptures were reported, representing 578 tagged red snapper. Sixty-five percent of recaptures (<em>n </em>= 412) were made at the site of release on subsequent research cruises, while 217 recaptures were reported by fishers. Eighty-six percent of individuals with known recapture locations moved 2 km or less from the site of release; mean and maximum distances moved were 2.1 km and 201 km, respectively. Nine red snapper moved greater than 80 km. Mean dispersion rate from release sites was 8.6 m d<sup>⁻1</sup>. Annual site fidelity of tagged fish was estimated using nonlinear decay models. Estimated annual site fidelity ranged from 48% to 52% year<sup>⁻1</sup> and was not significantly affected by artificial reef design, reef fish biomass at the site of release, or artificial reef densities surrounding each tagging site. Growth rates were estimated by regressing the change in red snapper total length versus the days a fish was at liberty. Mean growth rate for all recaptured fish was 0.206 mm d<sup>⁻1</sup>. Growth rates were significantly affected by reef size (faster at larger experimental reefs) and reef fish biomass (slower at tagging sites supporting low reef fish biomass), but were not affected by artificial reef density. Moderate site fidelity and low dispersion rates during our study provide support for the hypothesis that artificial reefs off Alabama are suitable habitat for adult red snapper. However, characteristics of artificial reefs, such as reef size and standing stock biomass, may affect red snapper growth. Furthermore, ratios of instantaneous growth in weight to total mortality (<EM>G/Z</EM>) suggest artificial reefs off Alabama serve as net sinks (i.e., <EM>G/Z </EM>< 1) of red snapper biomass under current fishing mortality rates.


<em>Abstract.</em>—Video estimation of the relative abundance of fishes is a noninvasive method commonly used to assess fish densities. This technique can be used to characterize habitat use patterns either of fish assemblages or of a particular species of interest. The objectives of this study were to quantify relative abundance of red snapper, <em>Lutjanus campechanus</em>, and to characterize with video methodology the associated fish assemblages over different habitat types. Fishes were enumerated over sand, shell, and natural hard bottom reef habitats in the north-central Gulf of Mexico (GOM) off Alabama on quarterly cruises over a two-year period with a baited stationary underwater video camera array. Red snapper showed both significantly higher abundance and larger size over the reef habitat; however, no seasonal effects were observed, indicating temporal abundance patterns were consistent among seasons. Fish assemblages differed among habitats, with significant differences between reef and shell assemblages. Efforts to identify the species that most contributed to these differences indicated that the red snapper accounted for 59% of the overall similarity within the reef fish assemblage and 20% of the total dissimilarity between the shell and reef fish assemblages. This study highlights the utility of applying video techniques to identify the importance of sand, shell, and reef habitat types both to different life stages of red snapper, and to the different fish assemblages occupying distinct habitats in the north-central GOM.


2017 ◽  
Vol 68 (10) ◽  
pp. 1955 ◽  
Author(s):  
James A. Smith ◽  
William K. Cornwell ◽  
Michael B. Lowry ◽  
Iain M. Suthers

Artificial reefs are a widely used tool aimed at fishery enhancement, and measuring the scale at which fish assemblages associate with these artificial habitat patches can aid reef design and spatial arrangement. The present study used rapidly deployed underwater video (drop cameras) to determine the magnitude and spatial scale of associations between a fish assemblage and a coastal artificial reef. Count data from drop cameras were combined with distance and bathymetry information to create a suite of explanatory generalised linear mixed models (GLMMs). The GLMMs showed that artificial reefs can influence surrounding fish abundance, but that the magnitude and scale is species specific. Three of the eight taxonomic groups examined showed a positive association with the artificial reef (with model fit poor for the remaining groups); and depth and bottom cover were also influential variables. The spatial scales of these associations with the artificial reef were small, and it was generally the presence of reef (i.e. a reef bottom type) that explained more variation in fish abundance than did distance to reef. The schooling baitfish yellowtail scad was an exception, and had elevated abundance >50m from the artificial reef. Further distribution modelling of artificial reefs will benefit species-specific design and management of artificial reefs.


<em>Abstract</em>.—Twenty artificial reefs were deployed early in October 2005 approximately 20 km south of Dauphin Island, Alabama (USA), in the Hugh Swingle General Permit Area. Each reef consisted of 12 concrete blocks (20 cm long × 20 cm wide × 41 cm high) arranged on a plywood base (1.5 m<sup>2</sup> )and deployed on the bottom, 20 m deep. To quantify the epibenthic assemblage on the reefs, four removable bricks were attached to the reefs. Ten reefs were coated with copper-based, anti-fouling paint and 10 reefs were unpainted. Fish and epibenthic assemblages were compared between reef treatments (i.e., with and without copper-based paint). Reefs were surveyed 1 week after deployment in October 2005, then again in December 2005, May 2006, August 2006, and December 2006. During each survey, two scuba divers visually estimated the densities of all fish species and removed one of the removable bricks to identify and quantify the epibenthic organisms. The epibenthos (coverage area, biomass, diversity, species richness) and fish assemblages (total fish density, species diversity, species richness) were greater on unpainted reefs. Red Snapper <em>Lutjanus campechanus</em>, wrasses <em>Halichoeres </em>spp., Bank Sea Bass <em>Centropristis ocyurus</em>, and Atlantic Spadefish <em>Chaetodipterus faber </em>had higher densities on unpainted reefs. This study indicated that recruitment of fishes to artificial reefs was not just attraction to structure, but that growth of epibenthic assemblages had a significant influence on recruitment.


<em>Abstract</em>.—Identifying morphometrics, age composition, and growth of Red Snapper <em>Lutjanus campechanus </em>(Poey, 1860) in the Gulf of Mexico is crucial for management of this valuable species. Red Snapper are highly associated with artificial reefs situated off the coast of Texas. Artificial reefs, two in federal waters (offshore) and two in state waters (inshore), were sampled quarterly from December 2014 through December 2016. Characteristic differences in age and growth patterns at inshore and offshore sites and across sampled sites were compared. Mean ± standard deviation was calculated for total length (TL), weight, and biological age. Red Snapper collected averaged 464.5 ± 92.6 mm in TL, 1.62 ± 1.03 kg, and 3.8 ± 1.5 years. Significant differences in TL, weight, and age were observed across sites but not between inshore and offshore locations. In comparing 12 previous Red Snapper length-at-age (0–25 years) studies across the Gulf of Mexico, results were similar except for two studies significantly different from one another, but none with respect to our study. Our findings suggest that Red Snapper populations are young and restricted to one or two spawning years before capture on artificial reefs. Continued management of fisheries associated with these reefs are necessary to increase the stock and eventually lead to robust and sustainable fisheries.


2019 ◽  
Vol 209 ◽  
pp. 49-57 ◽  
Author(s):  
Catheline Y.M. Froehlich ◽  
Andres Garcia ◽  
Richard J. Kline

2017 ◽  
Vol 5 (1) ◽  
pp. 21
Author(s):  
Laurentius T. X. Lalamentik ◽  
Unstain N. W. J. Rembet ◽  
Adnan S. Wantasen

A comprehensive research effort was directed to increase the ecological role of Putus-Putus island coral reefs. This study was an implementation of artificial reef technology as fish colonization locality. The artificial reefs were made of 20x20x100 cm-concrete blocks placed in 6 levels and located at the depth of 8-10 m. Reef fish observations were done three times in two locations. Environmental parameters, such as temperature, salinity and visibility, were also measured. Environmental parameters (temperature, salinity a. Water temperature (29.65oC and 29.64oC) supported the coral growth as well. Salinity distribution  was not significantly different among the study sites.  This study also found 37 reef fish species belonging to 18 families. Number of species varied with observed time and localities. Total number of individuals increased with number of fish species. Mean number of individuals and species of reef fish in locality B were higher than those in locality A. Moreover, the reef fish colonization rate in the study site followed the model y = 4.3801e0.5249x with R2= 0.9297 in the strait and y = 5.0397e0.5493x  with R2= 0.9297 for the Bay. Keywords: Artificial reefs, reef fish. Abstrak Suatu upaya penelitian yang komprehensif diarahkan untuk peningkatan fungsi ekologi terumbu karang Pulau Putus-Putus. Penelitian ini berupa penerapan teknologi terumbu buatan sebagai tempat hunian ikan. Terumbu buatan terbuat dari balok cor beton berukuran 20x20x100 cm bersusun 6 dan ditempatkan pada kedalaman 8-10 m. Pengamatan ikan karang dilakukan 3 kali di 2 lokasi berbeda. Parameter lingkungan, seperti suhu, salinitas, dan kecerahan, juga diukur.    Hasil pengukuran yang diperoleh (29,65 oC dan 29,64 oC) termasuk suhu yang optimal untuk pertumbuhan karang. Dari hasil penelitian, ditemukan 37 spesies yang masuk dalam 18 famili ikan karang. Jumlah spesies yang ditemukan bervariasi pada setiap waktu dan lokasi pengamatan. Pengambilan spesies ikan karang dilakukan pada 2 lokasi dengan masing-masing lokasi dilakukan 3 kali pengambilan sampel. Berdasarkan hasil yang diperoleh (tabel 03) dapat dilihat bahwa jumlah individu bertambah seiring dengan banyaknya jumlah spesies ikan karang yang didapat. Rata-rata jumlah individu dan jumlah spesies ikan karang pada lokasi B lebih banyak. Laju hunian ikan karang di lokasi penelitian mengikuti model y = 4.3801e0.5249x dengan R2= 0,9297 untuk lokasi Selat dan y = 5.0397e0.5493x  dengan R2= 0,9297 untuk lokasi Teluk. Kata kunci : Terumbu buatan, ikan karang


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