Worked examples

Example 1: A catch-and-release tarpon-style fishery

A local NGO wants to understand whether a catch-and-release tarpon-like fishery has changed over time. Fish are rarely kept, so landing data are almost useless. Fishers and guides, however, talk constantly about the number of eats and hookups they have in a day. The survey therefore focuses on eats, hookups, and maximum fish size.

Respondents are first asked how many years of experience they have, how many days they typically fish each year, how many hours they fish in a typical day, and what proportion of their fishing occurs in each region. The survey then asks about each region where they spend at least 10% of their fishing time. For each region, they are asked for their best ever day in terms of eats, their best ever day in terms of hookups, and the largest fish they ever caught. Each question asks for the year and the number. The survey then asks the same questions for the current year.

The analysis produces eats per standard fishing day, hookups per standard fishing day, and maximum size by year. Because the best day for eats may differ from the best day for size, the survey treats these as separate memories. This allows the assessment to show whether encounter rates and size structure have changed in the same way or whether they tell different stories.

Example 2: An invertebrate gleaning fishery

A coastal community collects invertebrates from intertidal seagrass meadows. Most harvest is eaten locally or sold informally, so there are no landing records. Harvesters describe catch in buckets, not kilograms. During the survey design meeting, local women explain that a “bucket” usually means a 10-litre household bucket filled to the rim, although some households use larger containers.

The BECCA asks each harvester about their best collecting day this year, their best ever collecting day, and their best collecting day when they first started. For each event, the interviewer records the number of buckets, the year, the number of hours spent collecting, the number of people collecting, the tide or season if remembered, and the general collection area. A short local unit exercise is then used to estimate how many invertebrates and how much weight one full bucket usually represents.

The analysis produces buckets per person-hour and, where conversion is reliable, kilograms per person-hour. The community validation meeting then helps interpret whether declines are linked to harvesting pressure, sediment change, water quality, market demand, access restrictions, or changes in who collects.

Example 3: A trap-based crab fishery

A small-scale crab fishery uses baited traps set overnight. Fishers do not think of catch in hours because the traps fish while they are away. They think in terms of number of crabs per trap set. The BECCA therefore records catch, number of traps, and soak time.

A fisher might say that in 2007 their best day was 300 crabs from 50 traps soaked overnight. In the current year, their best day might be 120 crabs from 80 traps. If the analysis used catch alone, the decline would appear moderate. But when standardised by trap effort, the change is much clearer. The historical best catch was six crabs per trap per soak, while the current best catch is 1.5 crabs per trap per soak.This example shows why effort matters. Without effort standardisation, BECCA can misread the fishery.

Example 4: A multi-species reef handline fishery

A reef handline fishery catches many species, and fishers sell catch in baskets at the landing site. During survey design, the field team learns that fishers can remember total baskets well, but species-specific baskets less reliably. The BECCA therefore records total reef fish catch, but also asks whether the catch was dominated by snapper, grouper, parrotfish, emperor, or mixed reef fish.

A respondent reports that their best day in 1995 was eight baskets from a six-hour trip with three crew. Their current-year best day was three baskets from seven hours with four crew. The analysis can calculate baskets per boat-hour and baskets per person-hour. If basket weight can be estimated, the data can also be converted to kilograms per person-hour.

The community validation discussion may reveal that catch composition has changed even where total baskets appear stable. This can trigger a follow-up survey or a more detailed species-specific BECCA.

Example 5: A traditional fish fence or weir fishery

A traditional fish fence catches fish moving with the tide. Fishers describe the best catches by sacks and by tide cycles, not by hours. The BECCA therefore records the year, number of sacks, number of tide cycles, number of people involved, and whether the catch came from one fence, one section, or a shared community structure.

The analysis may use sacks per tide cycle, or estimated kilograms per tide cycle if sack conversion is reliable. If the fish fence has changed in size or construction over time, this is recorded as context. The final report should be careful not to compare catches across decades without explaining changes in fence length, location, ownership, or access.