Description
This dataset is from a paper by Jennings and Polunin (1992) the looked at impacts of predator depletion by fishing on the biomass and diversity of non-target reef fish communities around the Kadavu Islands, Fiji.
An understanding of the indirect effects of fishing on predator-prey relationships is required for the development of valid multispecies yield models for reef fisheries and for determining the factors governing fish community structure at larger scales. We used an underwater visual census technique to examine the indirect effects of fishing on the biomass and diversity (species richness) of reef fishes in a series of ten traditional Fijian fishing grounds (qoliqoli) subject to a range of fishing intensities. All members of the families Chaetodontidae (butterflyfishes), Labridae (wrasses), Lutjanidae (snappers), Mullidae (goatfishes), Scaridae (parrotfishes) and the sub-family Epinephelinae (groupers and coral trout) which could be reliably identified were censused. Each species censused was assigned to one of three trophic groups: herbivore, invertebrate feeder or piscivore. The biomass of all piscivorous fishes and of large ('30 cm) piscivorous fishes differed significantly between qoliqoli and was significantly correlated with fishing intensity. However, the biomass of piscivorous fishes was not correlated with the biomass or diversity of their potential prey (which were not targeted by the fishery). This suggested that the indirect effects of fishing did not have an important bearing on fish diversity or biomass and that predation by the target species did not play an important role in structuring these Fijian reef fish communities. The results contrast with those from a number of studies at smaller scales and provided further indications that the structure of reef fish communities is not governed by a single dominant process, but by a range of processes which operate on different scales in different circumstances.
Enregistrements de données
Les données de cette ressource données d'échantillonnage ont été publiées sous forme d'une Archive Darwin Core (Darwin Core Archive ou DwC-A), le format standard pour partager des données de biodiversité en tant qu'ensemble d'un ou plusieurs tableurs de données. Le tableur de données du cœur de standard (core) contient 70 enregistrements.
2 tableurs de données d'extension existent également. Un enregistrement d'extension fournit des informations supplémentaires sur un enregistrement du cœur de standard (core). Le nombre d'enregistrements dans chaque tableur de données d'extension est illustré ci-dessous.
Cet IPT archive les données et sert donc de dépôt de données. Les données et métadonnées de la ressource sont disponibles pour téléchargement dans la section téléchargements. Le tableau des versions liste les autres versions de chaque ressource rendues disponibles de façon publique et permet de tracer les modifications apportées à la ressource au fil du temps.
Versions
Le tableau ci-dessous n'affiche que les versions publiées de la ressource accessibles publiquement.
1.2Comment citer
Les chercheurs doivent citer cette ressource comme suit:
Jennings S, Polunin N (2024). Data from: Impacts of predator depletion by fishing on the biomass and diversity of non-target reef fish communities (Kadavu Islands, Fiji). Version 1.2. Southwestern Pacific Ocean Biogeographic Information System (OBIS) Node. Samplingevent dataset. https://nzobisipt.niwa.co.nz/resource?r=fiji_reef_fish_jennings_polunin_1997&v=1.2
Droits
Les chercheurs doivent respecter la déclaration de droits suivante:
L’éditeur et détenteur des droits de cette ressource est Southwestern Pacific Ocean Biogeographic Information System (OBIS) Node. Ce travail est sous licence Creative Commons Attribution (CC-BY) 4.0.
Enregistrement GBIF
Cette ressource n'a pas été enregistrée sur le portail GBIF
Mots-clé
Samplingevent; Observation
Contacts
- Fournisseur Des Métadonnées ●
- Créateur ●
- Personne De Contact
- Researcher
- Créateur
Couverture géographique
Kadavu Islands, Fiji
| Enveloppe géographique | Sud Ouest [-19,07, 178,035], Nord Est [-18,61, 178,55] |
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Méthodes d'échantillonnage
Quantitative estimates of the abundance and size of target-fishes in the ten qoliqoli were made using an underwater visual census (uvc) point count technique based on that developed by Samoilys and Carlos (1992). We selected a point count technique because net movements of target fishes along the reef front (frequently a response to the prevailing current) would not bias abundance estimates as they would if transect techniques were used (Watson et al. 1995). Validation of the uvc point count methodology, and the benefits and disadvantages of the technique, were discussed by Samoilys (1992), Samoilys and Carlos (1992) and Jennings and Polunin (1995c).
| Etendue de l'étude | The study was conducted within ten fishing grounds (qoliqoli) on the western coast of Kadavu Island. The boundaries of each qoliqoli enclose an area of reef on which the inhabitants of specific villages have exclusive rights to fish. |
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Description des étapes de la méthode:
- All members of the families Chaetodontidae (butterflyfishes), Labridae (wrasses), Lutjanidae (snappers), Mullidae (goatfishes), Scaridae (parrotfishes) and the sub-family Epinephelinae (groupers and coral trout) which could be reliably identified were selected for study. Lethrinidae (emperors) are of key importance in the fishery (Jennings and Polunin 1995a) but were not included because the census methodology is inappropriate for these species (Jennings and Polunin 1995c). Abundance estimates of the target species were made at seven replicate sites in each qoliqoli. The sites were selected by dividing all areas of reef front (well-developed reef front sloping directly to a depth of at least 10 m, openly exposed to the open ocean, with low siltation rates and estimated mean coral cover in excess of 25%: as confirmed by direct underwater observation) in each qoliqoli into 100 m sections (on aerial photographs from the Australian Aerial Mapping 1994 survey conducted on behalf of the Land and Survey Department, Government of Fiji) and randomly selecting seven of these sites. At each site, the abundance and size of target fishes > 8 cm fork length was estimated within 12 adjacent census areas of 7 m radius by counting each fish and making an estimate of its length to the nearest 1 cm. The 12 areas were censused in a random sequence and each census area was centered on the 6 m depth contour (on the reef slope). Boundaries of each census area were estimated from as far above or to one side of the census area as the prevailing visibility permitted and counts of the wariest fishes began immediately. Species in each census area were recorded sequentially, the most active species being recorded first. When a count for one species was complete, all further movements of that species in or out of the census area were disregarded. The time required to complete a count was not standardized since this was dependent on the number and diversity of fish in the census area and the complexity of habitat to be searched. In practice, counts took 6-13 minutes. Following the count, the diameter of the census area was measured twice (once parallel with, and once perpendicular to, the reef slope) to determine the accuracy with which the dimensions of the census area had been estimated. In addition, the depth at the center of the census area was recorded to confirm that the area was centered on the 6 m depth contour. All counts were conducted by the same observer (SJ), during daylight hours, from September 1995 to January 1996.
- Accuracy of fish length estimation was maintained by practicing with objects of known length at intervals throughout the study period (57 lengths of plastic 2.0 cm diameter white plastic tube cut to lengths from 8 to 65 cm in 1 cm increments and threaded onto a 1.0 cm diameter rope in a haphazard sequence) and assessed using methods based on Polunin and Roberts (1993).
Citations bibliographiques
- Jennings, S. and Polunin, N.V.C., 1997. Impacts of predator depletion by fishing on the biomass and diversity of non-target reef fish communities. Coral reefs, 16, pp.71-82.
Métadonnées additionnelles
marine, harvested by iOBIS
| Identifiants alternatifs | https://nzobisipt.niwa.co.nz/resource?r=fiji_reef_fish_jennings_polunin_1997 |
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