Til innholdet




Prosjektnummer: 900954
Status: Avsluttet
Startdato: 01.01.2014
Sluttdato: 15.04.2014

Cost effective and reliable methods of capturing sea urchin for developing the sea urchin industry in Norway / Kostnadseffektive og pålitelige fangstmetoder for å utvikle kråkebolleindustrien i Norge

Project results
A series of experimental experiments were carried out to test the efficacy of three trap types, identify the optimal period of time to set the traps and also to test two bait types.

The results clearly showed that the round collapsible trap design were most effective with the highest catch rates. The simple rope traps were also effective at accumulating urchins into concentrated areas which would useful for dive or ROV collection.

The optimal period for setting the traps was 7 days (± 1–2 days) and this is the recommended set time for commercial operations. However, optimal catch periods may vary according to local environmental conditions (e.g. feed availability) and urchin abundance and commercial fishermen should take this into account.

The trials clearly showed that using fish bait was more effective than using algae baits but the former attracted much higher bycatch than the algae baits. The more bait stations (of either algae or fish bait) used the greater the catch but the higher catch rates must be weighed against the increasing cost and time required to set more bait stations. A quick, easy bait station is required (e.g. a net pocket in the netting) that would simplify setting baits. If this can be achieved then the project team recommends at least two bait stations in each trap, but increasing the number of bait stations would increase the catch rates.

The commercial trials undertaken as part of this study clearly show that it is absolutely essential to have some knowledge of the abundance of urchins, depth and bottom topography of an area prior to commencing fishing. This can be gained by fishing an area over a long period of time, or by undertaking rapid, relatively cheap surveys using mini ROVs as used in the salmon industry.

In summary the results of this study show there is considerable potential to utilise passive trapping to develop sea urchin fisheries and possible sea urchin roe enhancement ventures throughout Norway. The results of the study will be used in follow up commercial projects with Lynsskjellan AS (Lyngen) and Capefish As (Hønningsfjord) to develop these capture techniques on a commercial scale. The former intend to supply sea urchins into the local Norwegian market and the latter intend supplying sea urchins to international markets.

In Norwegian
Målet for dette prosjektet var å utvikle nye metoder for fangst av kråkeboller som kan være kostnadseffektive både i forhold til nødvendig infrastruktur (fartøy og utstyr) og driftskostnader. Disse nye metodene benytter seg av kråkebollenes evne til å klumpe seg sammen (aggregere) på objekter på havbunnen (passive fangstredskaper).

En serie eksperimentelle forsøk ble gjort for å teste egnetheten til tre typer feller for kråkeboller og finne den optimale ståtiden for hver redskapstype samt å prøve ut to typer agn.

Resultatene viser tydelig at de runde sammenleggbare teinelignende fellene som ble testet var de mest effektive med de høyeste fangstratene. De enkle taufellene var også effektive for å trekke til seg kråkeboller fra et større område og kan være nyttige i kombinasjon med ROV-fangst eller innsamling med dykkere.

Den optimale ståtiden for fellene var 7 døgn (± 1–2 døgn) og dette er den ståtiden vi anbefaler for kommersiell fangst. Imidlertid kan lokale miljøforhold (f.eks. næringstilgang), bunntopografi og tetthet av kråkeboller påvirke den optimale ståtiden og potensielle fiskere må ta dette i betraktning.

Forsøkene viste tydelig at fisk (sild) var et mer effektivt agn enn stortare, men fisk gav også mye større bifangst av andre bunndyr. Jo mer agn jo mer fangst (både med sild og stortare som agn) men den høyere fangstraten må veies opp mot kostnaden ved større agnforbruk og tiden som går med til egning. En enklere egningsmetode bør utvikles, for eksempel innsydde lommer i notlinen (agnpose)som fellene er laget av. Det anbefales å bruke minst to agnposer per felle, men flere agnposer vil øke fangsten.

De kommersielle forsøkene som ble gjennomført viser at det er av avgjørende betydning å ha kunnskap om forekomst og tetthet av kråkeboller i et område før man setter i gang med fangst. Denne kunnskapen kan man få gjennom å fiske i et område over lang tid eller ved å foreta raske og relativt rimelige forhåndsundersøkelser ved hjelp av små ROVer av typen som brukes til inspeksjoner av anlegg og fortøyninger i oppdrettsnæringen.

Denne studien viser tydelig at det finnes betydelig potensial i å utvikle et fiskeri etter kråkeboller ved hjelp av passive fangstredskaper. Både for direkte salg og for innsamling av kråkeboller som skal mellomlagres og fôres for å øke rogninnholdet. Resultatene vil bli brukt videre i oppfølgingsprosjekter med Lyngsskjellan AS (Lyngen) og Capefish AS (Honningsvåg) der en ønsker å utvikle teknikkene i kommersiell skala. Førstnevnte ønsker å forsyne det norske markedet med ferske kråkeboller og sistnevnte ønsker å eksportere kråkeboller levende til internasjonale markeder.
In Norway the biomass of the green sea urchin (Strongylocentrotus droebachiensis) is estimated to be a massive 80 billion individual animals, or 56,000 tons. Despite this huge biomass the production of sea urchins in Norway has been sporadic (between 10–100t) and the current annual harvest is less than 20 ton. If only a small percentage of this total population could be harvested sustainably (approximately 5 per cent or 2800 tons) this alone would be create a fishery equivalent to the S. droebachiensis fishery in Maine (2006) which employed over 500 people. The main bottleneck to the development of a sea urchin fishery in Norway is the ability to collect sea urchins reliably, efficiently and consistently, particularly in the northern parts of Norway where conditions can be severe. In, addition to being biologically feasible the fishing method must be logistically and economically viable.

There has been both research and commercial development into a number of techniques to harvest sea urchins in Norway but none have yet proved to be sufficient to fully develop a consistent fishery. Previous efforts have been directed at traditional traps, using SCUBA diving teams and more recently using a remotely operated underwater vehicle (ROV). Each of these has faced a number of difficulties in the conditions experienced in Norway, particularly in winter, and in the northern regions. Each method of harvest has advantages over the other but to date no study has conducted a cost/benefit analysis of each technique. Following the closure of Scan Aqua AS (based in Hammerfest) in 2010 an extensive report was undertaken to review why the venture was unsuccessful. In regard to fishing methods the authors estimated that catch rates of 300–600kg of urchins / day (a seasonal estimate of 30 tonne) using traditional traps could be achieved. They list the advantages of traps as being suitable for use in times of low visibility and that the urchins were in better condition than when harvested by divers. Using SCUBA dive teams the authors estimated it would be possible to have a catch rate of 1000–1500kg/day when the conditions were ideal with an average catch of 1250 kg / day. Dive operations were severely limited by logistics, weather and the underwater visibility. No diving was possible between May and August due to algal blooms and between November and January due to winter conditions. Direct costs were not included but dive operations required a boat, 2 crew members and a minimum of 3 divers. Scan Aqua AS also used a similar size team for exploratory dives to find new areas to harvest sea urchins which was extremely expensive.

More recent attempts to use divers to collect sea urchins by Norway Sea Urchin AS in Båtsfjord proved to be logistically difficult and not economically viable. Scan Aqua AS in Hammerfest also used an ROV especially designed for collecting sea urchins (the seabed harvester). They reported optimal catches of 125kg urchins in 25 minutes. However, average catch rates and the cost of using the ROV were not estimated. A study in 2012 conducted by Nofima, funded by FHF and run in collaboration with Norway Sea Urchin AS showed that a realistic catch rate of export quality sea urchins (excluding bycatch) using the ROV in Båtsfjord in the winter period was 660kg / day. Catch per unit effort was calculated in this project and could provide an accurate method of comparing different harvesting techniques in subsequent studies.

In order to establish a resilient and viable sea urchin fishery, based on live capture and immediate sale, or based on live capture and subsequent holding and fattening a cost efficient and reliable harvesting method must be found. Alternatively, it may be that a number of methods must be utilized, depending on the characteristics of different areas (such as environmental conditions, time of year and the conditions on the seafloor topography).

The current project intends to develop novel low cost harvesting techniques that may prove more economically viable due to their low cost in terms of both infrastructure (boat and associated equipment) and running costs. These novel techniques include utilising the aggregating behavior of urchins on any objects found on the sea floor second (passive trapping) as well as a low technology method of fishing (dredging). The dredge design will be based on the Icelandic dredge which has been in used commercially in Iceland for the past 10 years (in conjunction with dive surveys to determine urchin biomass and suitability of the bottom terrain). In addition to new fishing techniques, the use of a mini ROV for assessing sea urchin biomass and seabed terrain will be investigated. Previous large scale fishing efforts (e.g. Scan Aqua AS) and small scale (Norway Sea Urchin AS) have relied on SCUBA dive teams to undertake exploratory investigations on new fishing grounds which is both costly, time consuming and logistically challenging. The technique of utilising a mini ROV (now commonly used in the aquaculture industry), would be fast and cost effective and would provide a relatively cheap and mobile method for new entry fishermen to accurately quantity the biomass of sea urchins in any in any given area prior to applying for fishing licenses for these areas. The mini-ROV will also provide a pre fishing survey technique for testing the Icelandic dredge.
These new harvesting techniques could be used by the following:
1. New entry fishing vessels of relatively small size. These could deliver sea urchins for immediate sale or into land or sea-based holding facilities.

2. The existing Norwegian inshore fishing fleet (which would enable fishermen to fish sea urchins during periods of low activity without extensive modification to their boats). This type of fishing could service seasonal markets such as the Christmas demand for sea urchins in Italian markets.

3. Specifically designed sea urchin harvesting vessels that would deliver sea urchins to a processing plant, sell live sea urchins immediately on landing, or deliver them into land or sea-based holding facilities for roe enhancement.
It should be stressed that the harvesting methods developed in this project would not necessarily be the only techniques that would or could be used to further develop the sea urchin industry in Norway. For example ROV technology will continue to be developed in Norway  but the low cost techniques in this project will provide an alternative cost effective method of fishing sea urchins to complement future high technology (and more expensive) solutions and allow fishers to enter the fishery without large start-up costs. Alternatively, some of the techniques developed in the project may prove to be suitable for attracting and aggregating sea urchins so that they are considerably easier to catch with more technological methods such as the ROV.
To develop novel capture techniques that are economically viable due to their low cost in terms of both infrastructure (boat and associated equipment) and running costs (labour and fuel). These will include novel passive capture, dredging harvesting as well as the use of a mini ROV to establish urchin biomass and the suitability of bottom terrain for harvesting methods. These methods will be used to supplement more technological collection methods (such as the ROV) and to stimulate the harvesting of sea urchins in Norway.
Expected project impact
This project would provide the stimulus to encourage harvesting of sea urchins in Norway with the long term goal of establishing a large scale fishery that provided both fresh sea urchins (collected and sold directly into domestic and international markets) as well as large scale land or sea-based roe enhancement facilities (such as Scan Aqua AS in Hammerfest and Norway Sea Urchins in Båtsfjord). The project falls directly into the FHF directive for ‘better utilisation of marine resources’, specifically developing ‘underused marine species’ and has the potential to dramatically develop the sea urchin fishery in Norway. Given the potential size of the sea urchin fishery in Norway the potential benefits of the project far outway the costs.
Project design and implementation
The project will be divided into the following three tasks:

1. Design and test novel passive trapping techniques for harvesting sea urchins. Tests to be conducted in areas of known sea urchin abundance in Kvalsund, Tromsø.
a. Investigate trap designs that have been used and tested previously. Incorporate the most promising traditional trap design in the project testing (d) as a control.
b. Design two new and novel traps that can be easily used on small vessels as well as the existing fishing fleet. The designs will utilise the behavior of urchins to accumulate on any surface that is placed on the bottom of the sea (e.g. a long flat surface that can easily be hauled aboard a fishing vessel).
c. Investigate the optimal materials to make the novel traps from (i.e. do urchins attach more readily to some substrates compared to other substrates). Sea-based trials to be conducted at Kårvika, Tromsø.
d. Run a series of tests to investigate the most effective trap. Trials to be run in Kårvika, Kvalsund, Tromsø where there are known concentrations of sea urchins:
– Trials to include at least 3 trap designs and 3 replicates of each.
– Trials to be run for a minimum of 5 days to analyse the effectiveness of the traps over time.
– Monitoring each day will be undertaken to analyse how quickly the urchins accumulate in the traps or on the trap material.
– Daily monitoring will also show whether there is movement of urchins in and out of the traps, or on and off the trap material.
– Investigate the trapping efficiency over time; 1, 3, 5 days soak time (i.e. do urchin numbers increase with soak time or is there an optimal soak time for catch efficiency).
– Investigate how effective each trap design is regarding losses during hauling.
e. Investigate bait efficiency in terms of cost and catch efficacy
– Trials to be conducted at Kårvika using the most efficient trap from previous tasks and testing various baits

2. Test the most promising two passive trap designs on a commercial scale
a. From the testing in Task 1 choose 2 optimal designs for use on a commercial inshore fishing boat based in Kvalsund, Tromsø
b. One of the design features of the traps will be that it can easily be adapted for use in small boats as well as existing fishing vessels.
c. The commercial test will consist of 3–4 days fishing in Kvalsund and one other location around Tromsø in areas of known sea urchin density. The test will provide information on:
– The quantity of urchins caught
– The survival/size of urchins caught
– The catch efficiency of the traps

3. Reporting
Analyse catch data in relation to catch per unit effort and compare with previous SCUBA diving and ROV catch data results. Produce a short Nofima report (in Norwegian), a press release and a popular article (in Norwegian) in a fishing magazine to publicize these results and stimulate interest in sea urchin fishing.
Dissemination of project results
A Final Report will be produced at the conclusion of the project (Task 3) in Norwegian and English and a press release will be made in February/March 2013.