SHALLOW WATER HABITAT MAPPING AND REEF FISH STOCK ESTIMATION USING HIGH RESOLUTION SATELLITE DATA

Author(s):  
Vincentius P. Siregar ◽  
Sam Wouthuyzen ◽  
Andriani Sunuddin ◽  
Ari Anggoro ◽  
Ade Ayu Mustika

Shallow marine waters comprise diverse benthic types forming habitats for reef fish community, which important for the livelihood of coastal and small island inhabitants. Satellite imagery provide synoptic map of benthic habitat and further utilized to estimate reef fish stock. The objective of this research was to estimate reef fish stock in complex coral reef of Pulau Pari, by utilizing high resolution satellite imagery of the WorldView-2 in combination with field data such as visual census of reef fish. Field survey was conducted between May-August 2013 with 160 sampling points representing four sites (north, south, west, and east). The image was analy-zed and grouped into five classes of benthic habitats i.e., live coral (LC), dead coral (DC), sand (Sa), seagrass (Sg), and mix (Mx) (combination seagrass+coral and seagrass+sand). The overall accuracy of benthic habitat map was 78%. Field survey revealed that the highest live coral cover (58%) was found at the north site with fish density 3.69 and 1.50 ind/m2at 3 and 10 m depth, respectively. Meanwhile, the lowest live coral cover (18%) was found at the south site with fish density 2.79 and 2.18  ind/m2 at 3 and 10 m depth, respectively. Interpolation on fish density data in each habitat class resulted in standing stock reef fish estimation:  LC (5,340,698 ind), DC (56,254,356 ind), Sa (13,370,154 ind), Sg (1,776,195 ind) and Mx (14,557,680 ind). Keywords: mapping, satellite imagery, benthic habitat, reef fish, stock estimation

2013 ◽  
Vol 5 (2) ◽  
Author(s):  
Vincentius P. Siregar ◽  
Sam Wouthuyzen ◽  
Andriani Sunuddin ◽  
Ari Anggoro ◽  
Ade Ayu Mustika

<p>Shallow marine waters comprise diverse benthic types forming habitats for reef fish community, which important for the livelihood of coastal and small island inhabitants. Satellite imagery provide synoptic map of benthic habitat and further utilized to estimate reef fish stock. The objective of this research was to estimate reef fish stock in complex coral reef of Pulau Pari, by utilizing high resolution satellite imagery of the WorldView-2 in combination with field data such as visual census of reef fish. Field survey was conducted between May-August 2013 with 160 sampling points representing four sites (north, south, west, and east). The image was analy-zed and grouped into five classes of benthic habitats i.e., live coral (LC), dead coral (DC), sand (Sa), seagrass (Sg), and mix (Mx) (combination seagrass+coral and seagrass+sand). The overall accuracy of benthic habitat map was 78%. Field survey revealed that the highest live coral cover (58%) was found at the north site with fish density 3.69 and 1.50 ind/m<sup>2</sup>at 3 and 10 m depth, respectively. Meanwhile, the lowest live coral cover (18%) was found at the south site with fish density 2.79 and 2.18  ind/m<sup>2</sup> at 3 and 10 m depth, respectively. Interpolation on fish density data in each habitat class resulted in standing stock reef fish estimation:  LC (5,340,698 ind), DC (56,254,356 ind), Sa (13,370,154 ind), Sg (1,776,195 ind) and Mx (14,557,680 ind).</p> <p>Keywords: mapping, satellite imagery, benthic habitat, reef fish, stock estimation</p>


2021 ◽  
Vol 8 ◽  
Author(s):  
Gregory P. Asner ◽  
Nicholas Vaughn ◽  
Bryant W. Grady ◽  
Shawna A. Foo ◽  
Harish Anand ◽  
...  

Coral reefs are undergoing changes caused by coastal development, resource use, and climate change. The extent and rate of reef change demand robust and spatially explicit monitoring to support management and conservation decision-making. We developed and demonstrated an airborne-assisted approach to design and upscale field surveys of reef fish over an ecologically complex reef ecosystem along Hawai‘i Island. We also determined the minimal set of mapped variables, mapped reef strata, and field survey sites needed to meet three goals: (i) increase field survey efficiency, (ii) reduce field sampling costs, and (iii) ensure field sampling is geostatistically robust for upscaling to regional estimates of reef fish composition. Variability in reef habitat was best described by a combination of water depth, live coral and macroalgal cover, fine-scale reef rugosity, reef curvature, and latitude as a proxy for a regional climate-ecosystem gradient. In combination, these factors yielded 18 distinct reef habitats, or strata, throughout the study region, which subsequently required 117 field survey sites to quantify fish diversity and biomass with minimal uncertainty. The distribution of field sites was proportional to stratum size and the variation in benthic habitat properties within each stratum. Upscaled maps of reef survey data indicated that fish diversity is spatially more uniform than fish biomass, which was lowest in embayments and near land-based access points. Decreasing the number of field sites from 117 to 45 and 75 sites for diversity and biomass, respectively, resulted in a manageable increase of statistical uncertainty, but would still yield actionable trend data over time for the 60 km reef study region on Hawai‘i Island. Our findings suggest that high-resolution benthic mapping can be combined with stratified-random field sampling to generate spatially explicit estimates of fish diversity and biomass. Future expansions of the methodology can also incorporate temporal shifts in benthic composition to drive continuously evolving fish monitoring for sampling and upscaling. Doing so reduces field-based labor and costs while increasing the geostatistical power and ecological representativeness of field work.


Drones ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 50
Author(s):  
Mary K. Bennett ◽  
Nicolas Younes ◽  
Karen Joyce

While coral reef ecosystems hold immense biological, ecological, and economic value, frequent anthropogenic and environmental disturbances have caused these ecosystems to decline globally. Current coral reef monitoring methods include in situ surveys and analyzing remotely sensed data from satellites. However, in situ methods are often expensive and inconsistent in terms of time and space. High-resolution satellite imagery can also be expensive to acquire and subject to environmental conditions that conceal target features. High-resolution imagery gathered from remotely piloted aircraft systems (RPAS or drones) is an inexpensive alternative; however, processing drone imagery for analysis is time-consuming and complex. This study presents the first semi-automatic workflow for drone image processing with Google Earth Engine (GEE) and free and open source software (FOSS). With this workflow, we processed 230 drone images of Heron Reef, Australia and classified coral, sand, and rock/dead coral substrates with the Random Forest classifier. Our classification achieved an overall accuracy of 86% and mapped live coral cover with 92% accuracy. The presented methods enable efficient processing of drone imagery of any environment and can be useful when processing drone imagery for calibrating and validating satellite imagery.


2020 ◽  
Vol 6 (1) ◽  
pp. 1
Author(s):  
Mahmudin Mahmudin ◽  
Chair Rani ◽  
Hamzah Hamzah

Dynamite fishing is one of the causes of damage to the coral reef ecosystem in Indonesia. Fishing activities using explosives (dynamite fishing) occur because of the desire of fishermen to get a lot of catch with low cost in a short time. Kapoposang Water Park (WP) is a region rich in marine biological resources. However, dynamite fishing activities which are still found within the area have caused the coral reef ecosystem to be severely damaged. The results showed a lower difference in the percentage of live coral cover at dynamite fishing locations (DF1, DF2) compared to control locations (K1, K2). In addition, the highest average values of coral fish abundance were found at locations K1, DF1, and DF2. Conversely, the results of the analysis found the lowest fish abundance at the K2 location. Different from the average number of reef fish species that were higher at the control location (K1, K2) compared to dynamite fishing locations (DF1, DF2). For the target fish biomass there is no real difference between the control location and dynamite fishing.


2018 ◽  
Vol 5 (2) ◽  
pp. 164
Author(s):  
I Made Raditya Putra ◽  
I Gusti Ngurah Putra Dirgayusa ◽  
Elok Faiqoh

The existence of coral reef fish is closely related to the availability of coral reef resource as a habitat. Coral reef fish is a biota that has a fascination with a variety of color patterns and fascinating. Differences in coral cover conditions will affect the abundance of coral reef fish, especially those with strong linkages to living corals. This research was conducted in June - August 2017 by using line intercept transect (LIT) method for coral cover percentage and visual census method for biodiversity and biomass of coral reef fish with 3 research stations in Manggis waters, Karangasem. From the research results, it shows that the diversity index ranged between 2.54 - 2.70 which means the diversity of coral reef fish in the medium category and the stability of the community is in the medium. Furthermore, total biomass of coral reef fish ranged between 186,17 - 1692,08 kg / ha. The results stated that the percentage of live coral cover in Manggis waters ranged from 3.83% to 12.44% which means that live coral cover is categorized as bad. A very strong positive correlation between living coral conditions and coral reef fish biomass was 92.42%. Meanwhile, the relationship between living coral conditions and the diversity of coral reef fish had a strong positive correlation of 65.4%. The diversity of coral reef fish in waters is not only caused by live coral cover; however, it is caused by coral reef ecosystems that are associated in the bottom of the waters.


Author(s):  
Joel G. Becira ◽  
Benjamin J. Gonzales ◽  
Honorio B. Pagliawan

In Palawan, Philippines, Honda Bay is fast becoming a target recreational site for curious domestic and foreign visitors. The general objectives of this resource assessment are to gather information regarding status of the marine resources in Pandan Island, and to provide recommendations for their sustainable use. Assessment was done using line intercept transect (LIT), fish visual census (FVC) and an imaginary transect belt for coral cover, fish, and macro-invertebrates, respectively. Average live coral cover around Pandan Island can be categorized as good (57%), with stations 7 and 1 and 2 categorized as excellent (76-100%) and fair (26-50%) conditions, respectively. Some 178 fish species were recorded in Pandan Island waters of which seven (7) highly target and 29 common commercial fish species were found. The estimated total reef fish biomass around Pandan Island is 588 mt/ km2. A total of eight macro invertebrate (shells, etc.) species belonging to five families was found around Pandan Island. The study concluded that of these eight species, six are commercially important,Tridacnacro cea(taklobo), Tridacnasquamosa (taklobo), Hippopusporcellanus(taklobo), Trochusniloticus(topshell), Pinna nobilis (tarab), and Bohadschiamarmota (sea cucumber). Five of these species the T. crocea, T. squamosa, H. porcellanus, P. nobilis, and T. niloticus are listed as endangered species by International Union for Conservation of Nature.   Keywords - target species, macro-invertebrates, coral cover, coral reefs, reef fish, conservation


2020 ◽  
Vol 23 (3) ◽  
pp. 333-340
Author(s):  
Munasik Munasik ◽  
Aldion Adin Nugroho ◽  
Retno Hartati ◽  
Agus Sabdono ◽  
Sugiyanto Sugiyanto ◽  
...  

Artificial Patch Reef (APR) have been applied as a new method for Biodiversity Conservation Program at Panjang Island, Jepara since 2015. Previous study suggested that design and location of artificial reefs installation affected to abundance of reef fishes, associated with the artificial reef.  This study aims to investigated community structure of reef fishes associated to artificial patch reef comparing to reef fishes in nearby natural reefs. Assessment of coral reef condition on two habitats were conducted on July 2019, after 4 years deployment.  The results show that artificial patch reefs with a percentage of live coral cover are less than half of natural coral reefs, and have succeeded in increasing the abundance of reef fish with nearly the same density and community structure resembling reef fish in natural coral reefs. The similarity in community structure of the two habitats is probably due to the similarity in habitat type and morphology of the hard corals. The results indicate that Artificial Patch Reef (APR) reefs have increased the coral cover of Acropora branching and resulted in increased reef fish abundance which is compatible with reef fish communities associated with natural coral reefs around it. Aplikasi metode baru terumbu buatan Artificial patch Reef (APR) pada Program Konservasi Bioiversitas Pulau Panjang, Jepara telah dilakukan sejak 2015. Hasil studi menunjukkan bahwa pemilihan desain dan lokasi pemasangan terumbu buatan yang tepat akan meningkatkan kelimpahan ikan karang. Tujuan penelitian ini adalah untuk mengetahui keberhasilan penerapan terumbu buatan APR melalui kelimpahan ikan karang yang berasosiasi pada terumbu buatan dan terumbu karang alami di sekitarnya. Penilaian kondisi terumbu karang tersebut telah dilakukan pada Juli 2019 setelah 4 (empat) tahun pemasangan terumbu buatan. Hasil studi menunjukkan bahwa terumbu buatan dengan persentase tutupan karang hidup lebih kecil, separuhnya dari tutupan pada terumbu karang alami telah berhasil meningkatkan kelimpahan ikan karang dengan densitas hampir sama dan struktur komunitasnya menyerupai ikan karang yang berasosiasi dengan terumbu karang alami. Kesamaan struktur komunitas kedua habitat kemungkinan akibat kesamaan tipe habitat dan morfologi karang keras penyusunya. Hasil ini mengindikasikan bahwa terumbu buatan Artificial patch Reef (APR) telah meningkatkan tutupan karang bercabang Acropora dan berakibat terhadap meningkatnya kelimpahan ikan karang yang sesuai dengan komunitas ikan karang yang berasosiasi dengan terumbu karang alami di sekitarnya.


2019 ◽  
Vol 4 (2) ◽  
Author(s):  
Muh Hamsir ◽  
Al Furkan ◽  
Fajar Izas ◽  
Adiyaat Ridho Agam ◽  
Fitra Jaya

The biodiversity of the Tiworo Strait Conservation Area (KKLD) was highly potential to be developed. However, in recent years, potential utilization has begun to lead to environmental destruction due to the use of destructive fishing gear. Therefore, biophysical studies were needed to give an overview and outlook about the area in order to provide information on the condition of coral reefs, reef fish, mangrove, sea grass, scare/endemic biota and socioeconomic conditions as well as the cause of aquatic ecosystems destruction. The method used to collect the data in the field is by undertaking observation, interview, and literature study method. Observation of coral cover and benthos used was by Point Intercept Transect (PIT) method while for the reef fish, the method used was a visual water census (UVC). Quadratic transect method was used for observation of sea grass and mangrove ecosystem. Meanwhile, the socio-economic condition is done by interview survey technique. The observation result shows the coral condition of the Tiworo Straits KKLD was in the medium category with the mean percentage of live coral of 46%. The lowest percentage of live coral was located at Station 1 of Mandike Island (18%), and the highest was at the Indo Island Station (76%), which is categorized as very good. The number of individual reef fish is 1.217 individuals / m2, and benthos type that dominates was sea urchin. The highest density of mangrove trees was 4000 trees/ha and the lowest was 200 trees/ha. The types of sea grasses observed were Thallasia hemprichi and Ehalus acroides. People, in general, have a livelihood as a fisherman with gill net fishing gear and fishing platform.


Sign in / Sign up

Export Citation Format

Share Document