Line of action:

Marine ecosystems

Status:

Finalizado

Execution date:

2019

General:

To analyse the use of starfish as a raw material in various productive sectors.

Specific:

1. To analyse the nutritional profile and possible content of toxic substances in samples of starfish obtained from geographically separated locations along the Galician coast.

2. Analyze the presence of pathogens in sea star samples.

3. To evaluate the feasibility of using starfish as a raw material for the production of fertilizers or organic amendments for agriculture.

4. Assess the feasibility of using starfish as a raw material for the production of organic feed for aquaculture.

5. To evaluate the feasibility of using starfish as a raw material for the production of decorative elements produced by hand.

A1- OBTAINING STARFISH FROM GEOGRAPHICALLY SEPARATED LOCATIONS, BIOCHEMICAL ANALYSIS AND TREATMENT OF SAMPLES FOR THE PERFORMANCE OF SUBSEQUENT ACTIVITIES: The fishermen’s guilds along the Galician coast will provide the starfish and in these samples the nutritional profile, content of toxins, sulfated sterols (saponins), metals and pesticides will be determined. and determination of the presence of pathogens.

A2- KEEPING IN CAPTIVITY OF LIVE SPECIMENS OF THE SPECIES Marthasterias glacialis: The stars will be kept alive in the CETGA facilities to study the abundance and species of bacteria and other pathogens they contain. Complementary tests will be carried out to those of the A1, if necessary. A feasibility study of cultivation with different types of food will be carried out.

A3- USE OF STARFISH AS FERTILIZER OR ORGANIC AMENDMENT FOR ORGANIC FARMING: A FERTILIZER OR AMENDMENT WITH THE STARS WILL BE MADE, AND TESTED ON TWO CROPS IN THE ECO-GARDENS OF 2 OF THE ASSOCIATIONS, DETERMINING THE NUTRITIONAL QUALITY OF THE FINAL PRODUCTS AND THE PRESENCE OF METALS, TOXINS OR PESTICIDES.

A4- USE OF STARFISH AS RAW MATERIAL FOR AQUACULTURE FEED: A FEED WITH THE STARS WILL BE MADE, AND TESTED ON TROUT, TURBOT AND SEA BREAM, DETERMINING THE NUTRITIONAL QUALITY AND THE PRESENCE OF METALS, TOXINS OR PESTICIDES IN THE FINAL PRODUCTS.

A5- USE OF THE STARFISH FOR THE PRODUCTION OF HANDICRAFT PRODUCTS: The starfish will be dried and used to make handicraft items in artistic and/or occupational workshops of 3 associations of people with functional diversity. An art exhibition will be held with these products, and each association will then put these items on sale at a local craft fair, in order to carry out a pilot market analysis, whose economic returns will be donated to the associations. An art exhibition will be held with the best items crafted.

A6- DATA ANALYSIS: This activity includes actions for the final analysis of data and the writing of technical reports on the results of the different activities and the report of final conclusions, as well as the technical and economic justifications of the project.

A7- DISSEMINATION ACTIVITIES: The planned dissemination plan includes initial dissemination talks in the fishermen’s guilds and awareness-raising talks in the associations, a minimum of 2 press releases (initial and final), 2 or 3 publications and attendance at 2 national or international congresses. There will also be a final dissemination event in which the final results will be transferred to the brotherhoods and collaborators of the project, which will also be open to the general public.

1. BIOCHEMICAL ANALYSIS OF STARS FROM DIFFERENT GEOGRAPHICAL LOCATIONS

From the analysis of starfish from the different geographical locations, we found that the stars of the species Marthasterias glacialis have a significantly higher ash content than those of the species Asterias rubens. The ash content displaces the rest of the components, and may therefore have less fat and protein, which despite this does not show significant differences with the values shown by A. rubens.

In terms of metal content, starfish show a high content of calcium and sodium. No toxins have been found in the sea star samples analyzed, although saponins have been detected. The highest concentrations of saponins found in the species M. glacialis are attributed to Marthasteroside C, followed by Marthasteroside B (which has been described as having anti-inflammatory activities). On the other hand, for the species A. rubens, the highest concentrations found in all the samples analyzed have been in Ruberoside A and Ruberoside F. Further studies are needed to analyse the effects of saponins on animals and plants.

As for the microbiota present in the coelomic fluid of starfish, gammaproteobacteria predominate, mainly of the genus Vibrio. Among the bacteria detected, those described as possible pathogens for marine animals do not survive >50ºC, so they would be inactivated in the feed production process.

2. KEEPING STARFISH IN CAPTIVITY

In the trial of captive culture of specimens of starfish of both species, it was found that the species A. rubens adapts worse to culture, by far, than the species M. glacialis. In A. rubens, stars fed a frozen pasta diet (which contains spinach, xarda, mussel, and squid) retain their weight better, although their mortality is higher than in those fed a diet exclusively mussel. Diet does not generate statistically significant differences in weight gain, contrary to what happens with the Month and the interaction of Month-Diet, possibly due to the influence of the laying period, which is the reason why the differences are possibly more important in larger stars. The differences are due more to temporal variations than to diet.

3. USE OF STARS AS RAW MATERIAL FOR AGRICULTURAL FERTILIZERS

As for the fertilizers made with starfish, the results obtained from the cultivation of broccoli and carrots in the eco-gardens, compared to a control fertilizer of worm hummus, show a nutritional profile similar to that of the control fertilizer in the vegetables grown with the star fertilizer, resulting in similar biomass obtained. Starfish fertilizer has a high calcium content, so it could be useful for pH correction in acidic soils, as well as a high concentration of sodium and magnesium. In terms of classification, the passes obtained are classified as type B season tickets (RD 506/2013).

4. HARNESSING STARS AS RAW MATERIAL FOR AQUACULTURE FEED

Starfish meal, compared to fishmeal, shows a lower protein, fat and fibre content, due to its high ash content, which displaces the rest of the components. The concentrations of metals such as As, Cd, Pb and Hg found are below the maximum limits allowed by legislation for feed raw materials. Although the fatty acid profile of the feed is not significantly altered with the substitution of 15% fishmeal for star meal, in the nutritional profile of this feed we find a small decrease of 1.5% in protein content, a 2% increase in fat content and a significant increase of 5.2% in ash content.

The feeds were not effective in trout and turbot, due to poor feed acceptance, resulting in the death of turbot fed with star feed and maintenance, but without weight gain, of trout, compared to control feed. However, good results were obtained in sea bream, with both groups (control and experimental) achieving weight gains of 77-78%, with feed conversion rates of 1.93 in the control diet and 1.96 in the experimental diet.

Trout feeds, like sea bream feeds, have a lower protein content than turbot feeds. In the case of turbot, the protein must be of high quality and digestibility, and this may be one of the reasons why star feed offers a poor result. Another possible explanation for the results obtained is palatability: trout and turbot showed a lower appetite for feed with star meal, an effect not seen in sea bream.

The high ash content in starfish meal and its high hygroscopic capacity make it difficult to use as a raw material in fish feed. It would be possible, however, to reduce the ash content by means of a process of hydrolysing the flour, which would lead to an increase in the percentages of the remaining components and also eliminate the moisture problem. The solution to the palatability problem detected could be found in the inclusion of flavourings and flavourings in the feed.

According to our data, the efficiency of starfish meal A . rubens as a raw material in aquaculture feed depends on the target species, being inefficient in the case of trout and turbot, and efficient in the case of sea bream.

5. USE OF STARS FOR THE PRODUCTION OF HANDICRAFT PRODUCTS

As a third way, the use of discarded stars for the production of artisanal products was valued. After the exhibition of handicrafts and the survey carried out on the handicrafts made, we have verified the good acceptance of the handicrafts made, very varied, with visitors to the exhibition highlighting the quality and originality of the handicrafts made and becoming interested in the purchase of several items. With regard to the economic benefit, it is very variable if we take into account the time spent on the production of the items, with small items (magnets, key rings and pendants with resin being more profitable…).

Provincial Federations of Fishermen's Guilds of Lugo, Pontevedra and Coruña Federation of Mollusc Producers of the Ebro Delta (FEPROMODEL) National Association of Women in Fishing (ANMUPESCA) ADICAM (Association of Women Diagnosed with Breast and Gynecological Cancer) Merioambiental Classroom and the Fishermen's Guilds of Burela, Virxen do Monte-Camariñas, San Bartolomé-Noia, San Telmo-Porto do Son, San Pedro-Riveira, Carreira and Aguiño, Pobra do Caramiñal, San Julián-Illa de Arousa, Virxe do Rosario-Vilaxoán, San Gregorio-Raxó, San Telmo-Pontevedra, San Juan-Redondela, San Cipriano-Aldán Hío, Lorbé and Malpica de Bergantiños. Biostatech Noresga Aiguanatura dels Ports Alento, Association of Acquired Brain Damage of Vigo, ASEM, Galician Association against Neuromuscular Diseases and ASPANAEX, Association in favor of People with Intellectual Disabilities of the province of Pontevedra