Benthic habitats of Buck Island Reef National Monument

NOAA’s Center for Coastal Monitoring and Assessment’s Biogeography Branch has mapped and characterized large portions of the coral reef ecosystems inside the U.S. coastal and territorial waters, including the U.S. Caribbean. The complementary protocols used in these efforts have enabled scientists and managers to quantitatively compare different marine ecosystems in tropical U.S. waters. The Biogeography Branch used these same general protocols to generate three seamless habitat maps of the Bank/Shelf (i.e., from 0 ≤50 meters) and the Bank/Shelf Escarpment (i.e., from 50 ≤1,000 meters and from 1,000 ≤ 1,830 meters) inside Buck Island Reef National Monument (BIRNM). While this mapping effort marks the fourth time that the shallow-water habitats of BIRNM have been mapped, it is the first time habitats deeper than 30 meters (m) have been characterized. Consequently, this habitat map provides information on the distribution of mesophotic and deep-water coral reef ecosystems and serves as a spatial baseline for monitoring change in the Monument. A benthic habitat map was developed for approximately 74.3 square kilometers or 98% of the BIRNM using a combination of semi-automated and manual classification methods. The remaining 2% was not mapped due to lack of imagery in the western part of the Monument at depths ranging from 1,000 to 1,400 meters. Habitats were interpreted from orthophotographs, LiDAR (Light Detection and Ranging) imagery and four different types of MBES (Multibeam Echosounder) imagery. Three minimum mapping units (MMUs) (100, 1,000 and 5,000 square meters) were used because of the wide range of depths present in the Monument. The majority of the area that was characterized was deeper than 30 m on the Bank/Shelf Escarpment. This escarpment area was dominated by uncolonized sand which transitioned to mud as depth increased. Bedrock was exposed in some areas of the escarpment, where steep slopes prevented sediment deposition. Mesophotic corals were seen in the underwater video, but were too sparsely distributed to be reliably mapped from the source imagery. Habitats on the Bank/Shelf were much more variable than those seen on the Bank/Shelf Escarpment. The majority of this shelf area was comprised of coral reef and hardbottom habitat dominated by various forms of turf, fleshy, coralline or filamentous algae. Even though algae was the dominant biological cover type, nearly a quarter (24.3%) of the Monument’s Bank/Shelf benthos hosted a cover of 10%-<50% live coral. In total, 198 unique combinations of habitat classes describing the geography, geology and biology of the sea-floor were identified from the three types of imagery listed above. No thematic accuracy assessment was conducted for areas deeper than about 50 meters, most of which was located in the Bank/Shelf Escarpment. The thematic accuracy of classes in waters shallower than approximately 50 meters ranged from 81.4% to 94.4%. These thematic accuracies are similar to those reported for other NOAA benthic habitat mapping efforts in St. John (>80%), the Main Eight Hawaiian Islands (>84.0%) and the Republic of Palau (>80.0%). These digital maps products can be used with confidence by scientists and resource managers for a multitude of different applications, including structuring monitoring programs, supporting management decisions, and establishing and managing marine conservation areas. The final deliverables for this project, including the benthic habitat maps, source imagery and in situ field data, are available to the public on a NOAA Biogeography Branch website (http://ccma.nos.noaa.gov/ecosystems/coralreef/stcroix.aspx) and through an interactive, web-based map application (http://ccma.nos.noaa.gov/explorer/biomapper/biomapper.html?id=BUIS). This report documents the process and methods used to create the shallow to deep-water benthic habitat maps for BIRNM. Chapter 1 provides a short introduction to BIRNM, including its history, marine life and ongoing research activities. Chapter 2 describes the benthic habitat classification scheme used to partition the different habitats into ecologically relevant groups. Chapter 3 explains the steps required to create a benthic habitat map using a combination of semi-automated and visual classification techniques. Chapter 4 details the steps used in the accuracy assessment and reports on the thematic accuracy of the final shallow-water map. Chapter 5 summarizes the type and abundance of each habitat class found inside BIRNM, how these habitats compare to past habitat maps and outlines how these new habitat maps may be used to inform future management activities.

Assessment of natural resource conditions in and adjacent to Dry Tortugas National Park

This project characterized and assessed the condition of coastal water resources in the Dry Tortugas National Park (DRTO) located in the Florida Keys. The goal of the assessment was to: (1) identify the state of knowledge of natural resources that exist within the DRTO, (2) summarize the state of knowledge about natural and anthropogenic stressors and threats that affected these resources, and (3) describe strategies being implemented by DRTO managers to meet their resource management goals. The park, located in the Straits of Florida 113 km (70 miles) west of Key West, is relatively small (269 square kilometers) with seven small islands and extensive shallow water coral reefs. Significant natural resources within DRTO include coastal and oceanic waters, coral reefs, reef fisheries, seagrass beds, and sea turtle and bird nesting habitats. This report focuses on marine natural resources identified by DRTO resource managers and researchers as being vitally important to the Tortugas region and the wider South Florida ecosystem. Selected marine resources included physical resources (geology, oceanography, and water quality) and biological resources (coral reef and hardbottom benthic assemblages, seagrass and algal communities, reef fishes and macro invertebrates, and wildlife [sea turtles and sea-birds]). In the past few decades, some of these resources have deteriorated because of natural and anthropogenic factors that are local and global in scale. To meet mandated goals (Chapter 1), resource managers need information on: (1) the types and condition of natural and cultural resources that occur within the park and (2) the stressors and threats that can affect those resources. This report synthesizes and summarizes information on: (1) the status of marine natural resources occurring at DRTO; and (2) types of stressors and threats currently affecting those resources at the DRTO. Based on published information, the assessment suggests that marine resources at DRTO and its surrounding region are affected by several stressors, many of which act synergistically. Of the nine resource components assessed, one resource category – water quality – received an ecological condition ranking of "Good"; two components – the nonliving portion of coral reef and hardbottom and reef fishes – received a rating of "Caution"; and two components – the biotic components of coral reef and hardbottom substrates and sea turtles – received a rating of "Significant concern" (Table E-1). Seagrass and algal communities and seabirds were unrated for ecological condition because the available information was inadequate. The stressor category of tropical storms was the dominant and most prevalent stressor in the Tortugas region; it affected all of the resource components assessed in this report. Commercial and recreational fishing were also dominant stressors and affected 78% of the resource components assessed. The most stressed resource was the biotic component of coral reef and hardbottom resources, which was affected by 76% of the stressors. Water quality was the least affected; it was negatively affected by 12% of stressors. The systematic assessment of marine natural resources and stressors in the Tortugas region pointed to several gaps in the information. For example, of the nine marine resource components reviewed in this report, the living component of coral reefs and hardbottom resources had the best rated information with 25% of stressor categories rated "Good" for information richness. In contrast, the there was a paucity of information for seagrass and algal communities and sea birds resource components.

An integrated biogeographic assessment of reef fish populations and fisheries in Dry Tortugas: Effects of No-take Reserves

The Tortugas Integrated Biogeographic Assessment presents a unique analysis of demographic changes in living resource populations, as well as societal and socioeconomic benefits that resulted from the Tortugas Ecological Reserves during the first five years after their implementation. In 2001, state and federal agencies established two no-take reserves within the region as part of the Florida Keys National Marine Sanctuary. The northern reserve (Tortugas Ecological Reserve North) was established adjacent to the Dry Tortugas National Park, which was first declared a national monument in 1935. The reserves were designed to protect a healthy coral reef ecosystem that supports diverse faunal assemblages and fisheries, serves as important spawning grounds for groupers and snappers, and includes essential feeding and breeding habitats for seabirds. The unique ecological qualities of the Tortugas region were recognized as far back as 1850, and it remains an important ecosystem and research area today. The two main goals of the Tortugas Ecological Reserve Integrated Ecological Assessment were: 1) to determine if demographic changes such as increases in abundance, average size and spawning potential of exploited populations occurred in the Tortugas region after reserve implementation; and 2) whether short-term economic losses occurred to fishers displaced by the reserve. This project utilized a biogeographic approach in which information on the physical features (i.e., habitat) and oceanographic patterns were first used to determine the spatial distribution of selected fish populations within and outside the Tortugas Ecological Reserve. Before-and-after reserve implementation comparisons of selected fish populations were then conducted to determine if demographic changes occurred in reef fish assemblages. These comparisons were done for the Tortugas region and also for a subset of available habitats within the Tortugas Ecological Reserve Study Area. Social and economic impacts of the reserves were determined through: 1) analyses of commercial landings and revenues from fishers, operating in the Tortugas region before and after reserve implementation and 2) surveys of recreational tour guides. Analyses of the commercial landings and revenues excluded areas inside Dry Tortugas National Park because commercial fishing has been prohibited within park boundaries since 1992. Key findings and outcomes of this integrated ecological assessment are organized by chapter and listed below.

Integration of fisheries acoustics surveys and bathymetric mapping to characterize midwater-seafloor habitats of US Virgin Islands and Puerto Rico (2008-2010)

NOAA’s Coral Reef Conservation program (CRCP) develops coral reef management priorities by bringing together various partners to better understand threats to coral reef ecosystems with the goal of conserving, protecting and restoring these resources. Place-based and ecosystem-based management approaches employed by CRCP require that spatially explicit information about benthic habitats and fish utilization are available to characterize coral reef ecosystems and set conservation priorities. To accomplish this, seafloor habitat mapping of coral reefs around the U.S. Virgin Islands (USVI) and Puerto Rico has been ongoing since 2004. In 2008, fishery acoustics surveys were added to NOAA survey missions in the USVI and Puerto Rico to assess fish distribution and abundance in relation to benthic habitats in high priority conservation areas. NOAA’s National Centers for Coastal Ocean Science (NCCOS) have developed fisheries acoustics survey capabilities onboard the NOAA ship Nancy Foster to complement the CRCP seafloor habitat mapping effort spearheaded by the Center for Coastal Monitoring and Assessment Biogeography Branch (CCMA-BB). The integration of these activities has evolved on the Nancy Foster over the three years summarized in this report. A strategy for improved operations and products has emerged over that time. Not only has the concurrent operation of multibeam and fisheries acoustics surveys been beneficial in terms of optimizing ship time and resources, this joint effort has advanced an integrated approach to characterizing bottom and mid-water habitats and the fishes associated with them. CCMA conducts multibeam surveys to systematically map and characterize coral reef ecosystems, resulting in products such as high resolution bathymetric maps, backscatter information, and benthic habitat classification maps. These products focus on benthic features and live bottom habitats associated with them. NCCOS Centers (the Center for Coastal Fisheries and Habitat Research and the Center for Coastal Environmental Health and Biomolecular Research) characterize coral reef ecosystems by using fisheries acoustics methods to capture biological information through the entire water column. Spatially-explicit information on marine resources derived from fisheries acoustics surveys, such as maps of fish density, supports marine spatial planning strategies and decision making by providing a biological metric for evaluating coral reef ecosystems and assessing impacts from pollution, fishing pressure, and climate change. Data from fisheries acoustics surveys address management needs by providing a measure of biomass in management areas, detecting spatial and temporal responses in distribution relative to natural and anthropogenic impacts, and identifying hotspots that support high fish abundance or fish aggregations. Fisheries acoustics surveys conducted alongside multibeam mapping efforts inherently couple water column data with information on benthic habitats and provide information on the heterogeneity of both benthic habitats and biota in the water column. Building on this information serves to inform resource managers regarding how fishes are organized around habitat structure and the scale at which these relationships are important. Where resource managers require place-based assessments regarding the location of critical habitats along with high abundances of fish, concurrent multibeam and fisheries acoustics surveys serve as an important tool for characterizing and prioritizing coral reef ecosystems. This report summarizes the evolution of fisheries acoustics surveys onboard the NOAA ship Nancy Foster from 2008 to 2010, in conjunction with multibeam data collection, aimed at characterizing benthic and mid-water habitats in high priority conservation areas around the USVI and Puerto Rico. It also serves as a resource for the continued development of consistent data products derived from acoustic surveys. By focusing on the activities of 2010, this report highlights the progress made to date and illustrates the potential application of fisheries data derived from acoustic surveys to the management of coral reef ecosystems.

An ecological correction to marine reserves boundaries in the US Virgin Islands

Marine protected areas (MPAs) are important tools for management of marine ecosystems. While desired, ecological and biological criteria are not always feasible to consider when establishing protected areas. In 2001, the Virgin Islands Coral Reef National Monument (VICR) in St. John, US Virgin Islands was established by Executive Order. VICR boundaries were based on administrative determination of Territorial Sea boundaries and land ownership at the time of the Territorial Submerged Lands Act of 1974. VICR prohibits almost all fishing and other extractive uses. Surveys of habitat and fishes inside and outside of VICR were conducted in 2002-07. Based on these surveys, areas outside VICR had significantly more hard corals; greater habitat complexity; and greater richness, abundance and biomass of reef fishes than areas within VICR, further supporting results from 2002-2004 (Monaco et al., 2007). The administrative (political) process used to establish VICR did not allow a robust ecological characterization of the area to determine the boundaries of the MPA. Efforts are underway to increase amounts of complex reef habitat within VICR by swapping a part of VICR that has little coral reef habitat for a Territorially-owned area within VICR that contains a coral reef with higher coral cover.

St. John, USVI mission report: a strategy to inventory, characterize, and monitor the marine region within and around the National Park and Monument boundaries of St. John, USVI

The intent of this field mission was to continue ongoing efforts: (1) to spatially characterize and monitor the distribution, abundance and size of both reef fishes and conch within and around the waters of the Virgin Islands National Park (VIIS) and newly established Virgin Islands Coral Reef National Monument (VICR), (2) to correlate this information to in-situ data collected on associated habitat parameters, (3) to use this information to establish the knowledge base necessary for enacting management decisions in a spatial setting and to establish the efficacy of those management decisions. This work is supported by the National Park Service and NOAA’s Coral Reef Conservation Program’s Caribbean Coral Reef Ecosystem Monitoring Project.

Coral health and disease in the Pacific: vision for action

Shallow coral reefs in the IndoPacific contain the highest diversity of marine organisms in the world, with approximately 1500 described species of fish, over 500 species of scleractinian corals, and an estimated 1-10 million organisms yet to be characterized (Reaka-Kudla et al. 1994). These centers of marine biodiversity are facing significant, multiple threats to reef community and habitat structure and function, resulting in local to wide-scale regional damage. Wilkinson (2004) characterized the major pressures as including (1) global climate change, (2) diseases, plagues and invasive species, (3) direct human pressures, (4) poor governance and lack of political will, and (5) international action or inaction. Signs that the natural plasticity of reef ecosystems has been exceeded in many areas from the effects of environmental (e.g., global climate change) and anthropogenic (e.g., land use, pollution) stressors is evidenced by the loss of 20% of the world’s coral reefs (Wilkinson 2004). Predictions are that another 24% (Wilkinson 2006) are under imminent risk of collapse and an additional 26% are under a longer term threat from reduced fitness, disease outbreaks, and increased mortality. These predictions indicate that the current list of approximately 30-40 fatal diseases impacting corals will expand as will the frequency and extent of “coral bleaching” (Waddell 2005; Wilkinson 2004). Disease and corallivore outbreaks, in combination with multiple, concomitant human disturbances are compromising corals and coral reef communities to the point where their ability to rebound from natural disturbances is being lost.

Biogeographic characterization of fish communities and associated benthic habitats within the Flower Garden Banks National Marine Sanctuary: sampling design and implementation of scuba surveys on the coral caps

The Flower Garden Banks National Marine Sanctuary (FGBNMS) is located in the northwestern Gulf of Mexico approximately 180 km south of Galveston, Texas. The sanctuary’s distance from shore combined with its depth (the coral caps reach to within approximately 17 m of the surface) result in limited exposure of this coral reef ecosystem to natural and human-induced impacts compared to other coral reefs of the western Atlantic. In spite of this, the sanctuary still confronts serious impacts including hurricanes events, recent outbreaks of coral disease, an increase in the frequency of coral bleaching and the massive Diadema antillarum die-off during the mid-1980s. Anthropogenic impacts include large vessel anchoring, commercial and recreational fishing, recreational scuba diving, and oil and gas related activities. The FGBNMS was designated in 1992 to help protect against some of these impacts. Basic monitoring and research efforts have been conducted on the banks since the 1970s. Early on, these efforts focused primarily on describing the benthic communities (corals, sponges) and providing qualitative characterizations of the fish community. Subsequently, more quantitative work has been conducted; however, it has been limited in spatial scope. To complement these efforts, the current study addresses the following two goals put forth by sanctuary management: 1) to develop a sampling design for monitoring benthic fish communities across the coral caps; and 2) to obtain a spatial and quantitative characterization of those communities and their associated habitats.

St. John, USVI mission report, NOAA/NOS/NCCOS/CCMA/Biogeography Branch, July 6 - July 17, 2009

The intent of this field mission was to continue ongoing efforts: (1) to spatially characterize and monitor the distribution, abundance and size of reef fishes, and the abundance of macroinvertebrates (conch, Diatema, lobster) within and around the waters of the Virgin Islands National Park (VIIS) and newly established Virgin Islands Coral Reef National Monument (VICR), (2) to correlate this information to in-situ data collected on associated habitat parameters, (3) to use this information to establish the knowledge base necessary for enacting management decisions in a spatial setting and (4) to establish the efficacy of those management decisions. An additional focus this year, was to evaluate a new habitat data collection method for RHA sites (MSR and some Coral Bay sites). There are concerns that the cylinder habitat data are not reflective of the fish transect habitat. To address this, we collected habitat data at 5x4 m increments along the transect in addition to data collected using the cylinder method. We are currently assessing the potential differences between these methods and preliminary results indicate that the average difference of coral cover estimates between the two methods was 4.1% (range 0-11%) based on 16 sample sites. In addition, Erinn Muller, a Nancy Foster Fellowship recipient, collaborated with the Biogeography Branch to examine the spatial distribution of coral diseases, to provide baseline information on disease prevalence over varying spatial scales and to establish spatial distributions of coral diseases around St. John.

PCR-based assay for detection of four coral pathogens

Several microorganisms have been identified as pathogenic agents responsible for various outbreaks of coral disease. Little has been learned about the exclusivity of a pathogen to given disease signs. Most pathogens have only been implicated within a subset of corals, leaving gaps in our knowledge of the host range and geographic extent of a given pathogen. PCR-based assays provide a rapid and inexpensive route for detection of pathogens. Pathogen-specific 16S rDNA primer sets were designed to target four identified coral pathogens: Aurantimonas coralicida, Serratia marcescens, Vibrio shilonii, and Vibrio coralliilyticus. Assays detected the presence of targets at concentrations of less than one cell per microliter. The assay was applied to 142 coral samples from the Florida Keys, Puerto Rico, and U.S. Virgin Islands as an in situ specificity test. Assays displayed a high-level of specificity, seemingly limited only by the resolution of the 16S rDNA.

Temporal trends in reef fish assemblages inside Virgin Islands National Park and around St. John, U.S. Virgin Islands, 1988-2006

This report is a result of long-term fish monitoring studies supported by the National Park Service (NPS) at the Virgin Islands National Park since 1988 and is now a joint NPS and NOAA collaboration. Reef fish monitoring data collected from 1988 to 2006 within Virgin Islands National Park (VINP) and adjacent reefs around St. John, U.S. Virgin Islands (USVI) were analyzed to provide information on the status of reef fishes during the monitoring period. Monitoring projects were initiated by the National Park Service (NPS) in the 1980s to provide useful data for evaluation of resources and for development of a long-term monitoring program. Monthly monitoring was conducted at two reef sites (Yawzi Point and Cocoloba Cay) starting in November 1988 for 2.5 years to document the monthly/seasonal variability in reef fish assemblages. Hurricane Hugo (a powerful Category 4 storm) struck the USVI in September 1989 resulting in considerable damage to the reefs around St. John. Abundance of fishes was lower at both sites following the storm, however, a greater effect was observed at Yawzi Point, which experienced a more direct impact from the hurricane. The storm affected species differently, with some showing only small, short-term declines in abundance, and others, such as the numerically abundant blue chromis (Chromis cyanea), a planktivorous damselfish, exhibiting a larger and longer recovery period. This report provides: 1) an evaluation of sampling methods, sample size, and methods used during the sampling period, 2) an evaluation of the spatial and temporal variability in reef fish assemblages at selected reef sites inside and outside of VINP, and 3) an evaluation of trends over 17 years of monitoring at the four reference sites. Comparisons of methods were conducted to standardize assessments among years. Several methods were used to evaluate sample size requirements for reef fish monitoring and the results provided a statistically robust justification for sample allocation.

Mission report: a strategy to inventory, characterize, and monitor the marine region within and around the National Park and Monument boundaries of St. John, USVI, July 21- July 31, 2008

The intent of this field mission was to continue ongoing efforts: (1) to spatially characterize and monitor the distribution, abundance and size of both reef fishes and conch within and around the waters of the Virgin Islands National Park (VIIS) and newly established Virgin Islands Coral Reef National Monument (VICR), (2) to correlate this information to in-situ data collected on associated habitat parameters, (3) to use this information to establish the knowledge base necessary for enacting management decisions in a spatial setting and to establish the efficacy of those management decisions. This work is supported by the National Park Service and NOAA’s Coral Reef Conservation Program’s Caribbean Coral Reef Ecosystem Monitoring Project. The report highlights the successes of this mission.

Mesophotic coral ecosystems research strategy: international workshop to prioritize research and management needs for mesophotic coral ecosystems, Jupiter, Florida, 12-15 July 2008

On July 12-15, 2008, researchers and resource managers met in Jupiter, Florida to discuss and review the state of knowledge regarding mesophotic coral ecosystems, develop a working definition for these ecosystems, identify critical resource management information needs, and develop a Mesophotic Coral Ecosystems Research Strategy to assist the U.S. National Oceanic and Atmospheric Administration (NOAA) and other agencies and institutions in their research prioritization and strategic planning for mesophotic coral ecosystems. Workshop participants included representatives from international, Federal, and state governments; academia; and nongovernmental organizations. The Mesophotic Coral Ecosystems Workshop was hosted by the Perry Institute for Marine Science (PIMS) and organized by NOAA and the U.S. Geological Survey (USGS). The workshop goals, objectives, schedule, and products were governed by a Steering Committee consisting of members from NOAA (National Centers for Coastal Ocean Science’s Center for Sponsored Coastal Ocean Research, the Office of Ocean Exploration and Research’s NOAA Undersea Research Program, and the National Marine Fisheries Service), USGS, PIMS, the Caribbean Coral Reef Institute, and the Bishop Museum.

Review on hard coral recruitment (Cnidaria: Scleractinia) in Colombia

Recruitment, defined and measured as the incorporation of new individuals (i.e. coral juveniles) into a population, is a fundamental process for ecologists, evolutionists and conservationists due to its direct effect on population structure and function. Because most coral populations are self-feeding, a breakdown in recruitment would lead to local extinction. Recruitment indirectly affects both renewal and maintenance of existing and future coral communities, coral reef biodiversity (bottom-up effect) and therefore coral reef resilience. This process has been used as an indirect measure of individual reproductive success (fitness) and is the final stage of larval dispersal leading to population connectivity. As a result, recruitment has been proposed as an indicator of coral-reef health in marine protected areas, as well as a central aspect of the decision-making process concerning management and conservation. The creation of management plans to promote impact mitigation,rehabilitation and conservation of the Colombian coral reefs is a necessity that requires firstly, a review and integration of existing literature on scleractinian coral recruitment in Colombia and secondly, larger scale field studies. This motivated us to summarize and analyze all existing information on coral recruitment to determine the state of knowledge, isolate patterns, identify gaps, and suggest future lines of research.

Identification, diversity and distribution patterns of fish larvae in Khark & Kharko Coralline Islands ecosystem – Persian Gulf, by GIS method

Khark & Kharko Islands are the last Northern point for fringing coral reefs in Iranian side of the Persian Gulf. These Coralline habitats are the Protected Area and Wildlife Refugees with the total area of 2400 ha which located in the territory of Bushehr Province. This research carried out during 2006-2007 with monthly sampling from 12 stations, which selected around Islands and inshore waters with maximum depth of 20 meter. Sampling was conducted using by Bongo-Net plankton sampler with 500μ of mesh size. Totally, 1808 specimen from 45 family fish larvae was identified in studied area, including: 21 coralline fish larva families and 24 shore fish larvae such as pelagic and demersal fishes which some of them known as indicator, sentinel or endemic species for coral reef ecosystems. The results was shown that coral reef diversity in coral reefs (Khark & Kharko Islands) is more than other habitats such as estuary and river mouth, creeks, mangrove forest sites, and off shore water of the Persian Gulf and Oman Sea Iranian side. Among Identified families, Clupeidae, Blenniidae, Sillaginidae, Atherinidae and Tripterygiidae; with more abundance were dominant families in studied area. The pick of fish larvae abundance family were estimated in spring. There were significant differences between seasonally abundance and sub areas, but there were not significant differences in diversity indexes between Khark and Kharko stations with coastal stations (p< 0.05). The mean abundance of fish larvae were estimated 18.7083 larvae under 10m² of sea surface, and the mean diversity indexes and evenness were estimated 0.7135 and 0.565342 consequently, that was showed the area is under ecological stress for fish larvae, and wasn’t stable. Therefore, from the ecological point of view, only some of the fish larvae groups as like Clupeidae were dominant. Thus, they were the main cause of the fish larvae abundance change in studied area. Due to geographical location of Khark and Kharko Islands and among the environmental parameters, Its seems that the condition of sea current is the main cause for present or absent and distribution patterns of fish larvae in area. Abundance of fish larvae in west of Islands was higher than eastern parts in the spring. But this condition will be reversed in eastern part of Island and several coastal stations, so that the Islands surrounding clock wise current to cause fish larvae distribution patterns.