Marine resources and their value in Kadavu, Fiji

Recognition of the multiple types of value of marine resources is crucial to help design locally meaningful and sustainable management approaches for marine and coastal habitats. There is a lack of information on the amount of living marine resources harvested by coastal communities in many Pacific Island Countries and Territories (PICTs), as well as on their economic and non-economic value. This paper explores the monetary, subsistence, and sociocultural value of selected marine resources (finfish and invertebrates) in Kadavu province, Fiji, based on a household survey and semi-structured interviews conducted in 2019 within one specific district. The paper provides estimates of the annual catch and monetary value of marine resources harvested by local communities at both the district and provincial levels, derived from catch and effort information collected from fishers and gleaners in situ. It also highlights the importance of integrating the sociocultural significance of marine resources into future value assessments. Supplementary Information The online version contains supplementary material available at 10.1007/s13280-022-01794-0.


Goal:
To better understand the value of marine resources harvested by coastal communities in Kadavu Introduction to respondents:  Introduce yourself and who you work for  Explain the survey will take about 30 minutes  State that information will be confidential:  Will only release aggregated / anonymous data (no personal information)  Final report will be available on the IMR website or can contact IMR or Kadavu Provincial office for a copy

A-Adjusting for seasons and weather conditions
The range of questions asked in the survey (Appendix S1, section 2) regarding fishing and gleaning in different seasons and weather conditions is designed to ensure that the study is representative of fishing conditions on Kadavu for a full calendar year. The number of good/bad weather days was taken into account for the catch estimates by calculating the mean number of days per month that had good or bad weather according to the fishers' or gleaners' responses on weather. The catch responses from fishers or gleaners were then adjusted to provide a more realistic estimate of actual days spent fishing or gleaning per month. This was done by adjusting the 'number of days fishing or gleaning' responses of individual fishers and gleaners for each weather and season combination by the estimated proportion of days per month that had good or bad weather in each season. The catch estimates were next adjusted for the probability (as a proportion of 1) of having a good, normal, or bad catch in either good or bad weather. This probability was estimated by calculating the averages from the responses provided for Table 4 of the questionnaire (Appendix S1, section 2). Factoring in the range of catch (maximum, average, minimum) and the effect of weather and season is a standard method to reduce bias in interview-derived data (O'Donnell et al. 2012).

B-Finfish and invertebrate categories
Finfish categories included: reef fish (twelve families along with an 'other' category), four types of pelagic fish (small pelagic, coastal pelagic, offshore pelagic, and tuna), and elasmobranchs (sharks and rays). For reef fish, fishers were also asked if they targeted particular families when fishing. Invertebrate taxa harvested by fishers included: molluscs (giant clam, reef squid, and octopus), crustaceans (lobster, crab, and shrimp), and holothurians (sea cucumbers). The main habitats where each category of finfish was caught were recorded using the following categories: back reef / lagoon, fore reef slope, reef channel, mangrove, seagrass, deep water or 'other'. Habitat categories for gleaning differed with 'mud' and 'rocks' replacing fore reef slope, reef channel, and deep water.

C-Conversion of catch records to weight and value
The weights of finfish and invertebrates were derived from a combination of stated sizes (length) and/or weights (in kg or bundles 1 ). For finfish, the mean sizes of reef or pelagic fish were calculated using both the information collected from interviewees for unsold fish, and fish size data collected in Kavala Bay for sold fish as part of the TAILS monitoring programme 2 in 2017-2018. These mean sizes were used to convert catch data for individual fish into weight (Table S2), using the length-weight (L/W) relationships available for reef or pelagic fish genera or species on Fishbase (www.fishbase.in).
Regional estimates for the L/W relationships were used where available on Fishbase. Weights were calculated separately for sold and unsold fish as semi-commercial fishers were generally selling the larger fish in their daily catch and keeping the smaller ones for food.
Catch records for reef fish families were analysed to determine relative fishing pressure at the family level. For some fishers, the sum of the responses for individual reef fish families was greater than the single response for reef fish total catch. It was assumed that some fishers had over-estimated the daily catch when responses were recorded for individual reef fish families. Therefore, to assess relative fishing pressure on reef fish families, the proportion of each family caught by fishers on a daily basis was calculated for fishers who provided responses as catch weights (bundles or kg). Catch proportions were calculated for the different fishing methods and for all types of fishing combined.
In a few cases, only the number of individuals for the total reef fish catch were recorded. For these data, the responses provided for reef fish families were used to calculate the proportion of the total catch per family. These proportions were then used to estimate the weight of the total reef fish catch (using the mean lengths for sold or unsold fish at the family or genus level). The average of the sold and unsold lengths were used for some calculations for fishers who primarily fished commercially but kept a proportion of their catch for local consumption as these fishers were targeting a range of fish sizes.
After comparing the responses for total reef fish caught to the sum of the results for reef fish families it was decided to use the total reef fish responses to calculate annual estimates of catch and value. The reasoning for this was that some fishers overestimated the catch for reef fish families so that when the records for individual families were summed up they substantially exceeded the single response for total reef fish catch. The latter was therefore regarded as the more accurate measure of reef fish catch.
Catch estimates were converted to monthly amounts, seasonal amounts (6 months each for cyclone and non-cyclone seasons), and finally an annual catch estimate. Occasional catches were factored in by asking key informant fishers how often they would catch categories that were harvested more occasionally, e.g. once in five trips for coastal pelagic fish. Seasonal catches were included where recorded for specific parts of the year, e.g. six out of 12 months for tuna.
The extrapolation of catch data to the district level was based on the mean catches of individual fishers or gleaners multiplied by the mean number of people per household practicing each type of marine resource collection (fishing, fishing and gleaning, or gleaning only). This was then multiplied by the number of households in the district.
Catch estimates were converted to monetary value based on unpublished local values for sold or unsold (retained) finfish or invertebrates using the prices charged by fishers or gleaners on Kadavu. These selling prices were collected either during the household survey or from key informants for the same time period that the surveys were conducted in 2019 (see Table S1). For reef fish, the values used were set as a standard of $25 per bundle when sold commercially. The selling price did vary according to point of sale and whether the fisher was mainly fishing commercially or occasionally sold some of the catch. For example, the selling price within a community was generally less than that charged by commercial fishers e.g. $10-20 per bundle rather than $25. Fish prices did not change between seasons but were affected by other factors such as the knock-on effects of the COVID-19 lockdown in 2020 where fishers from Nakasaleka (Matasawalevu) travelled to Vunisea rather than Kavala to sell their catch when the inter-island ferry service was postponed. The longer travel distances by boat resulted in a price of $35 per bundle rather than $25 to cover the increased fuel costs. It is not known if Kadavu fish prices were published in annual reports of the Ministry of Fisheries but records of local fish prices were kept at the ministry's fisheries stations on Kadavu in Vunisea and Kavala.  Where: L = length, W = weight, cm = centimetres, g = grams, n.d. = no data. Lengths in brackets were estimates based on discussions with key local informants.