Artificial Reef Fish Research Articles

Comparative evaluation of fish assemblages census on an artificial reef

One of the main issues regarding artificial reef fish evaluation is the performance of an efficient visual census sampling. An experimental artificial reef made of four different types of concrete modules was implanted on the north coast of Rio de Janeiro (21º29'S, 41º00W). Two interval-sampling periods using a visual census method were performed in the summer of 2003 (N = 6) and 2004 (N = 6), weekly and daily, respectively. The longer interval-sampling period showed twice of species with eight exclusive ones. Total fish abundance was higher during the shorter interval-sampling period, due to the presence of large shoals of Chloroscombrus chrysurus (Linnaeus, 1766) and Haemulon aurolineatum (Cuvier, 1829) especially at the complex modules. Fish abundance according to vertical position and feeding habits in the two interval sampling-periods showed a clear association to the structural complex modules, reinforcing the shelter influence on local fish assemblage structure and composition. The second survey showed quite different diversity and taxonomic results and highlighted the impossibility of obtaining several independent samples in a short period.of time.

Resource analysis of the Chinese society 1980–2002 based on exergy—Part 4: Fishery and rangeland

This fourth part is the continuation of the third part on agricultural products. The major fishery and rangeland products entering the Chinese society from 1980 to 2002 are calculated and analyzed in detail in this paper. The aquatic production, mainly relying on freshwater and seawater breeding, Enhancement policy of fishery resources, including closed fishing season system, construction of artificial fish reefs and ecological fish breeding, etc., is discussed in detail. The degradation of the major rangeland areas, hay yields and intake rangeland resources by the livestock, are also described associated with the strategic adjustment and comprehensive program to protect rangeland resources during the study period.

Effects of substrate on the artificial reef fish assemblage in Santa Eulalia Bay (Ibiza, western Mediterranean)

We studied the fish assemblage on an artificial reef southeast of the island of Ibiza (western Mediterranean) in relation to the type of substratum on which reef units are deployed: Posidonia meadow or bare sand. Data were collected by visual census over the course of 2 years. Species richness and abundance were determined for the total assemblage and for separate guilds, as well as their size composition. Mean species richness was higher on meadow units because of the large number of species belonging to the Labridae. The results indicate that most species are habitat-specific. Comparing these results with those from another reef in Balearic waters highlights the effect of a Posidonia meadow on reef colonization.Copyright 2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved.

Experimental Study on Wave-Generated Sound Pressure from Bottom Seated Submerged Structures

Installing artificial fish reefs is expected to improve and preserve sea environment as well as fish cultivation. In order to attain such objectives, fish reefs should have adequate function to gather fish. In this research, the wave generated sound from fish reef is considered to be one of the important factors to gather fish. Laboratory experiments were carried out to measure the sound pressure from fish reef models. In the experiments, number of fish reef models and their arrangements were changed and their effects on generated sound pressure were investigated. Numerical analysis was also conducted to calculate flow conditions around them. It was confirmed that the sound pressure in front of structures is more pronounced by installing another structure in far side.

Studies on the Biological Function of Artificial Fish Reefs

Studies on the Biological Function of Artificial Fish Reefs

The impact of artificial‐reef fish assemblages on their potential forage area

Artificial reef fish assemblages have the potential to alter the trophic structure of the nearby fauna by changing the available forage food. As the number and biomass of fish attracted to artificial reefs increases, they can reduce the potential energy available to sustain the assemblage. During 1994 we investigated the impact that artificial reef assemblages had on the proximate infauna in the forage area immediately surrounding several artificial reefs in the northern Gulf of Mexico. The forage community parameters (number of individuals, taxonomic richness, biomass, and diversity) were compared from areas which had no reefs to areas around reefs. Our analysis indicates there was considerable variation in the infauna in all areas. The number of individuals was lower near the reefs but was at the background level about 80 m from the reefs. Number of taxa was lower next to the reef and increased slightly away from the reefs but was much lower than background species richness. Species diversity was higher in the area near the reefs. To optimize the potential yield from artificial reefs, managers should recognize the potential impact that the reef fish assemblage can have on the available food resources needed to sustain a viable artificial reef fish assemblage.

Development of Tagging Techniques for Monitoring Fish Populations at Texas Artificial Reefs

Texas Parks and Wildlife Department (TPWD) has used a broad range of methodologies to monitor the social, economic, and biological impacts of artificial reefs in the Gulf of Mexico. Social and economic issues have been addressed through charter boat and diver mail-in questionnaire surveys and on-site creel surveys. Biological issues have been investigated through hook and line tagging, diver-based visual transects, and video traps. Assessments of hydroacoustic and remotely operated vehicle (ROV) biological survey techniques are also planned for deepwater reef sites. There is also a need to develop inexpensive biological monitoring methods to track target fish populations such as red snapper over time at specific reef sites. The Department has been investigating the use of collapsible traps to tag fish underwater as a potential long-term monitoring tool for assessing reef fish populations. The cost effectiveness and efficiency of this gear type was compared to hook and line capture techniques. During the initial effort, 223 red snapper were tagged underwater by divers after capture by three collapsible traps, and 291 red snapper were tagged on the surface by anglers after capture by hook and line techniques. The collapsible traps appeared to be more size selective for smaller sized red snapper than hook and line techniques. Fish tagged underwater had a higher recapture rate of 25.45 percent compared to the 11.89 percent recapture rate for fish caught and tagged on the surface. Although three recapture periods were used to evaluate tag return data, our findings suggest that future efforts directed at monitoring artificial reef fish populations should use multiple gear types with equal effort applied to account for size-selective capture patterns and logistical constraints.

Experimental Study on Sound Pressure Generated by Wave-Submerged Structure Interaction

This study is intended to discuss the sound pressure generated by the wave-submerged structure interaction, which is considered to play an important role on fish gathering function of an artificial fish reef. Laboratory experiments were carried out to measure a sound pressure as well as the velocity and free surface variation. In the experiments, idealized simple structures were employed and flow visualization was also conducted. It is confirmed that the installation of the submerged structure generates the sound pressure on several frequency domains. Moreover, it is revealed that the variation of sound pressure depends much on vortex formation and its behavior.

Comparison of fish assemblages among an artificial reef, a natural reef and a sandy-mud bottom site on the shelf off Iwate, northern Japan

Fish assemblages at an artificial reef site, a natural reef site and a sandy-mud bottom site, on the shelf (depth 130 m) off Iwate Prefecture, northern Japan, were surveyed by using a bottom trammel net from May 1987 to March 1993. A total of 12 173 fishes of 48 species were recorded. Physiculus maximowiczi was dominant and comprised 69% of the total numerical abundance. Total fish number was lowest in March at all the 3 sites when P. maximowiczi migrated to deeper and warmer waters. Assemblage equitability and species diversity also varied seasonally in accordance with the abundance fluctuation of P. maximowiczi. P. maximowiczi, Alcichthys alcicornis and Hexagrammos otakii were more abundant at the artificial reef and natural reef sites, while Dexistes rikuzenius and Hemitripterus villosus were more abundant at the sandy-mud bottom site; total fish abundance was largest at the artificial reef site mainly due to the large number of P. maximowiczi. Species richness was similar among sites, but equitability, and consequently species diversity, was lowest at the artificial reef site. The main effect of the artificial reef seemed the attraction of P. maximowiczi from nearby bottoms, especially from natural rocky reefs; its large abundance determined the structure of the artificial reef fish community.

Evaluation of Marine Environment Based on Growth of Marine Organisms

To avoid the environmental deterioration due to installation/construction of coastal structures, the assessment procedure for marine environment should be investigated. To attract fishes and the other marine organisms on artificial fish reef or the other type of coastal structures, the biological investigation of sesentary organisms and benthos is generally required. It is effective to investigate the attached organisms on silt curtains, for overview the habitat of attached marine organisms on coastal structures. Because silt curtains develop in various marine environments, that is in various water depth under wave and current actions. This paper discussed the relationship between the marine environment and the attached organisms on silt curtains.

Experimental Study on Characteristics of Local Scour and Embedment of Fish Reef by Wave Action

The characteristics of local scour and embedment of Artificial Fish Reef (AFR) by wave action are investigated experimentally, and the mechanism of embedment is discussed. With selected models of AFR, the experiment was conducted in a twodimensional wave tank. The vortex patterns near the angled part of AFR are also observed by the hydrogen-bubble method. The patterns of scour, the maximum scour depth, the embeded volume and the bottom-contact area of AFR model are revealed to be controled by KC number and shape of AFR on the movable bed.

Experimental Study on Wave-Generated Sound from a Bottom Seated Submerged Structure

Installing artificial fish reefs is expected to play important roles on improvement and preservation of sea environment as well as fish cultivation.As far as its effects are concerned, fish reefs should have adequate function to gather fish. In this research, the wave generated sound from fish reef is considered to be one of the most important factor to gather fish and the sound from fish reef models was measured by conducting laboratory experiments.Spectral analysis of measured sound shows that the vortex caused by wave and structure interaction generates the sound.The frequency, however, is much higher than that of vortex formation and behavior of vortex affects the properties of generated sound.

Similarity Law of the Model Test of Local Scour Depth Around Artificial Fish Reef due to Current

Similarity Law of the Model Test of Local Scour Depth Around Artificial Fish Reef due to Current

A Study on Local Scour of Cylindrical Artificial Fish Reefs

A Study on Local Scour of Cylindrical Artificial Fish Reefs

水深３０ｍの人工魚礁におけるマダカアワビＨａｌｉｏｔｉｓ ｍａｄａｋａの行動

The behavioral character of the abalone Haliotis madaka was examined around the artificial fish reef settled at 30m depths. Fourteen abalone, 11.0-18.3cm in shell length, were pursued their stuck places and shell length individually for 4 times during 16 months. Ten of 14 abalone were observed within 1m during 16 months. Two abalone, 18.3 and 17.4 cm in shell length, were photographed for a few days by an automatic underwater camera. In the daytime, two abalone firmly stuck at the same position. In the night time, they lift their shell slightly and ocassonally changed their body-axis to catch drifted algae. One abalone left it's stuck place and returned to the same position in one night during three observed nights.

A Solar Photovoltaic System for Marine Ranch

A 10.7 kW photovoltaic system for a marine ranch was installed on a concrete barge on the sea and has been in operation since August 1986. The system consists of two power lines and line 1 supplies power to responsible loads through storage batteries while line 2 supplies surplus power directly to an artificial fish reef for electro-deposition. As a result, all the generated power is utilized efficiently. Acquired data show that the system operated normally with a high system efficiency of 7.1 %. The cost of generated electricity is estimated to be several times less than that of conventional one supplied with zinc-air battery.

ダイバーとの比較からみた魚礁での無人機の魚類観察能力について

Recently underwater observations have begun with small ROVs (Remotely operated vehicle) to observe marine biological resources. The ROV has several advantages compared to diver, because of less limits of observation time and working depth. ROVs are expected to be a good method for biological study around artificial fish reefs. The ability of small observation ROV and divers to distinguish fishes were compared at four characteristic bottom sites. As the result, the ability of ROV was not good enough at the bad visibility areas where young fishes inhabited, but was good at flat bottom areas and relatively good at the artificial reef. In regard to the number of fish species found at the artificial fish reefs settled at a depth of 30m, results of 20 min observations by two divers were superior to those of 360 min ROV observations. When using the ROV for the fishery research in artificial fish reef grounds, the results obtainable are unsuitable to quantitative analysis and extreme care must also be taken not so as to stragle the ROV's cable with fish reefs.

Fishing Effect of Artificial Fish Reefs off Fukude in the Sea of Enshu

Fishing Effect of Artificial Fish Reefs off Fukude in the Sea of Enshu

Experimental Study on Subsidence of Artificial Fish Reef due to Scour

Experimental Study on Subsidence of Artificial Fish Reef due to Scour

Flow Fields around the Artificial Fish Reef Models

Flow Fields around the Artificial Fish Reef Models