Manager   •   over 8 years ago

Problem Statement 15-9: "Develop a measuring board (or other system) that could automatically measure and record fish length."

NOTE: This is a featured problem statement. Featured problem statements have been qualified for post-Fishackathon engagement by both the submitting party and by our expert panel. While all of the submitted problem statements qualify for the prizes, these have vetted for contunuation beyond the event itself.

One solution for addressing overfishing is a TURF-Reserve. A TURF-Reserve consists of two main components: (1) Territorial Use Rights for Fishing (or TURFs), in which a group of fishers is assigned secure, exclusive privileges to fish in a designated area and (2) a Marine Reserve (or Reserve), which is a designated area where no fishing or extractive activities are permitted. A well-designed and well-managed TURF-Reserve has the potential to produce a variety of biological, economic, and social benefits.

In a TURF-Reserve, catch reporting provides information for setting fisheries management controls. Catch reporting also provides indicators of the effectiveness of the TURF-Reserve in meeting fishery goals, which allows the TURF-Reserve Management Body to adapt fisheries management controls over time.

Catch reporting is a common way of collecting fishery data. It involves regular reporting of fishers’ catch and fishing activity according to a specified protocol. Reporting can be done by the fishers themselves and/or by a designated monitor. Broadly, catch reporting data can indicate what species are being caught, how much, where, when, and how, thereby allowing fishery stakeholders to assess trends in:
• The volume of harvest over time (increasing, decreasing, remaining the same).
• The size, weight, and sex of the species caught.
• The amount of fishing effort being applied.
• The catch per unit of effort (CPUE) applied.
• Other fishery characteristics, such as fishing methods and locations.

Problem Statement
A catch reporting system relies heavily on the willingness and ability of fishers to accurately record and submit data on a regular basis. This process is not only time-consuming for fishers, but may also be challenging. Several data-limited stock assessment approaches rely on fairly straightforward data on the length-composition of the species of concern along with certain life history information. Length-composition data is gathered by measuring the individual lengths of fish that are caught in the fishery. However, handling fish can be messy. In order to measure individual fish lengths while also recording data in a logbook or computer takes at least two people, one to handle and measure the fish and one to record the data. Fishers often use a wooden board or measuring tape to measure fish length. Developing a measuring board (or other system) that could automatically measure and record fish length in a database would greatly increase efficiency of catch reporting.

Additional Background
The following video tells the story of La Encrucijada, Mexico. The fishing cooperatives of La Encrucijada established five fish recovery zones, or reserves. The reserves, combined with the exclusive fishing access of the cooperatives, represent the first time Rare has aided in the creation of a TURF-reserve (territorial rights in fisheries) in Mexico.
Working with fishers on a catch reporting system was an important part of engaging fishers in managing the fish recovery reserves. The fishing cooperatives were already calculating cumulative daily catch, but not for individual fish species; nor were they identifying specific fishing methods. Alejandro Arrivillaga, Rare’s monitoring manager in Latin America, visited La Encrucijada to help fishers improve their logbook system. Captivated fishers huddled around Arrivillaga’s small laptop screen.

“Usually you lose people with charts and so much mind-numbing data,” says Arrivillaga. “My main surprise was the fisher’s interest.” Arrivillaga showed them pictures of fish they catch every day and asked them to identify the species. It made fishers feel like the experts in the room. They started to make connections using the charts, for example, fish catch increases in March and April due to high demand for fish during Easter time. The fishers now keep detailed and improved logs of their catch, which benefits themselves while helping Rare and CONANP monitor and gauge conservation progress at the site.

You can view an example of the wooden boards fishers currently use to measure fish length in the 5:00 minute mark of the video. Having a board (or other system) that could automatically measure fish length when an individual (or multiple) fish were placed on it would greatly improve the efficiency of data collection and fisher participation in the catch reporting system.

Video link:

Core Category

Organization Name

Organization Address
1310 N. Courthouse Rd, Ste 110, Arlington, VA 22201

Organization Point of Contact (Name)
Kate Mannle

Organization Point of Contact (Title)
Sr. Manager, Program Development

Organization Point of Contact (Phone Number)
(703) 522 5070 ext. 139

Organization Point of Contact (Email Address)

Focus Area
Data Collection

Solution Category


  •   •   over 8 years ago

    Hello Fishackers! We at Rare are very excited to be a part of the 2015 Fishackathon. I'll be available all weekend to answer your questions- just send me an email at and we can setup a time to chat, Skype, Google hangout, etc. Also feel free to leave your questions here and I will do my best to answer them.

  •   •   over 8 years ago

    Has anyone thought about a solution such as this?

    Where fish would be held down with one hand and a picture would be snapped with the other? Is this more efficient? Would this solution be applicable, given the context?

  •   •   over 8 years ago

    Hi Jerod, I think something like that could work (though I've never seen it applied to this context before!). It might be tricky to hold the fish in one hand and take a picture of it with the other. Would arms-length be enough distance to get the measurement right? Would it be possible to do something similar but with the fish lying down and the camera above? That would probably be a lot easier for the fishers to manage (keeping in mind that switching between handling the fish and the cell phone could also be a barrier). The technology that's used to capture check deposits for mobile banking apps is coming to mind. You might need some sort of frame of reference though.

  •   •   over 8 years ago

    Me and Fu Yong Quah are working on this one in London, using an OpenCV based method. Hope to present in ~12 hours!

  •   •   over 8 years ago

    Good luck Tom and Fu!! Greetings from the Greenwave team in NYC

  •   •   over 8 years ago

    Fantastic! Good luck Tom and Fu! I would love to watch your presentation via Hangout, etc. Is there someone in London I can connect with?

  •   •   over 8 years ago

    Of course - we can invite you using the email posted,, if that's good with you?

    We will be showing in about 1.5 hours.

  •   •   over 8 years ago

    Perfect. My hangout address is Thanks!

  •   •   over 8 years ago

    Brilliant, super looking forward to it!

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