Indonesian Fish Research Articles

Addition of Nilem Fish Protein Concentrate to Find Its Preferred Level in Cakwe

Nilem fish (Osteochilus hasselti) are native Indonesian fish that live in freshwaters, such as rivers and swamps. This research aims to determine the right level of nilem fish protein concentrate addition to the preferred level of cakwe. The design is using a non-factorial Completely Randomized Design (CRD), with four levels of treatment like 0% or without the addition of nilem fish protein concentrate, 2.5% addition of nilem fish protein concentrate, 5% addition of nilem fish protein concentrate, and 7.5% addition of nilem fish protein concentrate. The parameters tested are organoleptic showing color, aroma, texture, and taste carried out by 20 semi-trained panelists. The results showed that cakwe with 5% nilem fish protein concentrate is mostly preferred by consumers with organoleptic values (color 6.9, aroma 7.3, texture 6.5, and taste 7.3).

The Proximate Analysis of Cakwe with Addition of Nilem Fish Protein Concentrate

Nilem fish (Osteochilus hasselti) are native Indonesian fish that live in freshwaters, such as rivers and swamps. This research aims to obtain the composition of proximate cakwe with the addition of nilem fish protein concentrate. Proximate parameters observed were water content, protein content, fat content, and ash content using the Association of Official Analytical Chemists (AOAC) method. This research was conducted from March 2019 to January 2020 at the Laboratory of Fishery Product Processing, Faculty of Fisheries and Marine Sciences, Padjadjaran University and Laboratory of Chemistry Research, PPBS, Padjadjaran University. The method used is an experimental method with the treatment of 5% nilem fish protein concentrate. The proximate test results showed that cakwe with the addition of nilem fish protein concentrate contained 27.72% water content, 10.42% protein content, 5.36% fat content, and 4.38% ash content.

Development of Genetically Improved Farmed African Catfish, Clarias gariepinus; A Review and Lessons Learned from Indonesian Fish Breeding Program

African catfish, Clarias gariepinus, is an introduced species and has been an important food supporting the fulfillment of food security in Indonesia. Along with increasing popularity as a farmed fish, it gradually showed lower aquaculture performance due in part to the deterioration of genetic quality of fry resulting from inappropriate and uncontrolled of broodstock. An African catfish breeding program aimed to cope with the problem was set in 2010 at the Research Institute for Fish Breeding, Sukamandi, Indonesia. Started with four founder populations, namely Egypt (29%), Paiton (27%), Sangkuriang (24%), and Dumbo (20%), a synthetic base population was established in 2011, and an individual selection targeting on growth improvement was conducted. A hundred broodstock were spawned to produce breeding candidates, and 5 percent of best-performing fish were selected in each generation. Genetic parameters (genetic gain and genetic variability) and a series of aquaculture performance-related traits including growth, feed conversion ratio (FCR), productivity, resistance to disease, size uniformity, and benefit/cost ratio were recorded. Following three successive generations of selection, over 50% of the accumulative genetic gain was obtained. This genetic gain consisted of 20%, 11%, and 20% from the first, second, and third generations, respectively. Field farm tests aiming at comparing the aquaculture performance of the selected strain against the existed local strains also showed promising results. It was 10-40% better in growth, 15-70% better in productivity, 2-9 times higher in benefit-cost ratio, shorter growing period (45-60 days), lower feed conversion ratio (0.6-0.8 in nursery and 0.6-1.0 in grow out) and higher survival (60-70%) following challenge test against Aeromonas hydrophyla infection. It also produced a higher uniformity in size, 80-90% in the fry production stage, and 70-80% in grow-out production. It seemed that there was an indication of positively correlated responses among growth and those traits. Selective breeding in African catfish by applying individual selection carried out at RIFB was managed to obtain a significant genetic improvement while maintaining genetic diversity.

Gut and intestinal biometrics of the giant trevally, Caranx ignobilis, fed an experimental diet with difference sources of activated charcoal.

Background: The giant trevally, Caranx ignobilis, is a commercially important marine fish in Indonesia. This species was initially cultured in Aceh Province. Previous reports showed that charcoal has a positive effect on survival and feed utilization of the giant trevally. However, the effects of adding charcoal to the diet on gut and intestine biometrics has, to our knowledge, never been described. Methods: Four activated charcoal sources were tested in this study using a completely randomized experimental design; coconut shell charcoal, mangrove wood charcoal, rice husk charcoal, and kernel palm shell charcoal. All treatments were performed with four replications. Juvenile giant trevally (average body weight, 16.52 ± 3.12 g; and average total length, 10.26 ± 0.64 cm) were stocked into the experimental tank at a density of 15 fish per tank. The fish were fed an experimental diet twice daily at 7 AM and 5 PM ad satiation for 42 days. Results: Analysis of variance showed that adding charcoal to the diet had significant effects on the length and width of the foveola gastrica and villous intestine (P < 0.05). The greatest length and width of the foveola gastrica was recorded in fish fed an experimental diet of rice husk charcoal with average values of 311.811 ± 9.869 µm and 241.786 ± 10.394 µm, respectively. The greatest length of intestinal villous was found in fish fed the mangrove wood charcoal diet, with a value of 135.012 ± 5.147 µm, but this length was not significantly different to that in fish fed rice charcoal and kernel palm shell charcoal. However, the greatest width of intestinal villous was recorded in fish fed the control diet (without charcoal; P < 0.05). Conclusion: The optimal sizes of the foveola gastrica and villous intestine were found in fish fed an experimental diet with rice husk charcoal.

Genetic differences and population structure of spotted barb (cyprinidae) collected from three rivers in Java Island

Barbodes binotatus is an endemic species and most dominant freshwater fish in Indonesia. This prelilinary study aimed to calculate genetic differences of the species from three different rivers in Java island. A total of 90 specimens were collected from each river and a total of 26 sequences were analyzed using mitochondrial DNA (mtDNA) region Cytochrome Oxidase Subunit I (COI). BLAST analysis showed > 97 % similarity of B. binotatus with another research. The result of sequence analysis showed that B. binotatus from Central Java were not significantly different from B. binotatus from East Java, and B. binotatus from West Java were significantly different from two others. The genetic differences of B. binotatus from three locations were observed in five basepair (335 bp, 399 bp,449 bp, 497 bp, and 545 bp). The result of population structure analysis showed an FST value of 1.00. It suggested that there was genetic differentiation between populations of Pasuruan, Yogyakarta and Cirebon. Inter-location analysis requires to be done to confirm the genetic differences from another regions.

Peningkatan Kesadaran Masyarakat untuk Gemar Makan Ikan: Pelatihan Pembuatan Es Dawet Belut Manis

Pelatihan pembuatan Es Dawnis dilatar belakangi oleh melimpahnya hasil dari budidaya belut di Desa Kandri, serta kurangnya konsumsi ikan di Indonesia. Program ini bertujuan untuk meningkatkan pemanfaatan belut sebagai upaya menggalakkan gerakan gemar makan ikan. Program ini berfokus masyarakat Desa Wisata Kandri terdapat tiga tahapanya itu pemaparan mengenai potensi dan kandungan gizi belut, pelatihan pembuatan Es Dawnis, dan pemasaran Es Dawnis. Dari ketiga tahapan tersebut dapat disimpulkan bahwa program pelatihan pembuatan Es Dawnis telah berhasil dilaksanakan dengan melihat antusias peserta, penerimaan produk, serta pemasaran produk yang dapat berpotensi mengenalkan Es Dawnis sebagai minuman Khas DesaWisata Kandri.

Sustainable wastewater management in Indonesia's fish processing industry: Bringing governance into scenario analysis

The government of Indonesia has pledged to meet ambitious greenhouse gas mitigation goals in its Nationally Determined Contribution as well as reduce water pollution through its water management policies. A set of technologies could conceivably help achieving these goals simultaneously. However, the installation and widespread application of these technologies will require knowledge on how governance affects the implementation of existing policies as well as cooperation across sectors, administrative levels, and stakeholders. This paper integrates key governance variables--involving enforcement capacity, institutional coordination and multi-actor networks--into an analysis of the potential impacts on greenhouse gases and chemical oxygen demand in seven wastewater treatment scenarios for the fish processing industry in Indonesia. The analysis demonstrates that there is an increase of 24% in both CH4 and CO2 emissions between 2015 and 2030 in the business-as-usual scenario due to growth in production volumes. Interestingly, in scenarios focusing only on strengthening capacities to enforce national water policies, expected total greenhouse gas emissions are about five times higher than in the business-as-usual in 2030; this is due to growth in CH4 emissions during the handling and landfilling of sludge, as well as in CO2 generated from the electricity required for wastewater treatment. In the scenarios where there is significant cooperation across sectors, administrative levels, and stakeholders to integrate climate and water goals, both estimated chemical oxygen demand and CH4 emissions are considerably lower than in the business-as-usual and the national water policy scenarios.

Analysis of Calcium (Ca) and Potassium (K) Levels in Mackerel (Rastrelliger sp.) Bones

Mackerel (Rastrelliger sp.) is one of the potential pelagic fish in Indonesia and in almost all Indonesian waters. In general, fish bones contain many essential ingredients for the body and can be processed into fish bone flour. This study aimed to determine calcium (Ca) and potassium (K) levels in mackerel (Rastrelliger sp.) bones. Calcium and potassium levels were determined using an atomic absorption spectrophotometry (AAS). Results of the analysis showed that the water, ash, and biomass levels of the sample were 10.53, 18.26, and 71.21%, respectively. Analysis of calcium and potassium levels at wavelengths 422.7 nm and 766.5 nm obtained an average of 508.15 and 36.37 mg/100g. The results indicate that the calcium level is higher than the potassium level in mackerel (Rastrelliger sp.) bones.

KEPADATAN POPULASI DAN NISBAH KELAMIN IKAN BUTUH KELENG (Butis butis) DI SUNGAI BELAWAN

Belawan River stores a fairly high diversity of fish, one of which is the crazy fish ( Butis butis ). A study of the bioecology of crazy fish has not done in Indonesia. They are considering the lack of bioecology of this fish in Indonesia. At the same time, bioecology data is needed by various parties as data and important information to know the condition of the fish population in nature. The purpose of this research is to know the population density and genital ratio of fish need keleng in Belawan River. This research is exploration. The location of fish sampling used a purposive sampling method. Fish arrested one time each month using a fishing rod. The collected fish are taken in total length and weight and identified the type of gender. Processing data using the application program Microsoft Excel 2010. The results showed the population density of fish at Station 1 (0.91 individual/m 2 ), Station 2 (0.92 individual/m 2 , and station 3 (0.35 individual/m 2 ). Sex ratio at Station 1, male fish (66%) and female (34%), Station 2, male fish (50,60%) and females (49,40%) and Station 3, male (50,77%) and females (49,23%).

Gut and intestinal biometrics of the giant trevally, Caranx ignobilis, fed an experimental diet with difference sources of activated charcoal

Background : The giant trevally, Caranx ignobilis, is a commercially important marine fish in Indonesia. This species was initially cultured in Aceh Province. Previous reports showed that charcoal has a positive effect on survival and feed utilization of the giant trevally. However, the effects of adding charcoal to the diet on gut and intestine biometrics has, to our knowledge, never been described. Methods : Four activated charcoal sources were tested in this study using a completely randomized experimental design; coconut shell charcoal, mangrove wood charcoal, rice husk charcoal, and kernel palm shell charcoal. All treatments were performed with four replications. Juvenile giant trevally (average body weight, 16.52 ± 3.12 g; and average total length, 10.26 ± 0.64 cm) were stocked into the experimental tank at a density of 15 fish per tank. The fish were fed an experimental diet twice daily at 7 AM and 5 PM ad satiation for 42 days. Results : Analysis of variance showed that adding charcoal to the diet had significant effects on the length and width of the foveola gastrica and villous intestine (P < 0.05). The greatest length and width of the foveola gastrica was recorded in fish fed an experimental diet of rice husk charcoal with average values of 311.811 ± 9.869 µm and 241.786 ± 10.394 µm, respectively. The greatest length of intestinal villous was found in fish fed the mangrove wood charcoal diet, with a value of 135.012 ± 5.147 µm, but this length was not significantly different to that in fish fed rice charcoal and kernel palm shell charcoal. However, the greatest width of intestinal villous was recorded in fish fed the control diet (without charcoal; P < 0.05). Conclusion: The optimal sizes of the foveola gastrica and villous intestine were found in fish fed an experimental diet with rice husk charcoal.

Latent Securitisation of Illegal, Unreported and Unregulated (IUU) Fishing in Indonesia

This paper aims to explore and explain to what extent and in what ways the Indonesian Government has securitised the Illegal, Unreported and Unregulated (IUU) fishing in Indonesia since 2009, by utilising critical discourse analysis. Using the Securitisation theory from the Copenhagen School, this paper explains the analysis of the speech act and extraordinary measures from SBY’s administration, Jokowi’s first term and second term administration. While IUU fishing has been a severe global issue, 30 percent of the cases take place in Indonesia and it becomes a serious threat for the economy and maritime resources. In 2009, Indonesia amended the fisheries law by establishing the new article about the right to burn and sink illegal foreign vessels. However, the securitisation remained ‘latent’ as it lacks the extraordinary measures and supporting speech act from the government. In 2014, during Jokowi’s first term, Indonesia had done extraordinary measures by regularly sinking the illegal foreign vessels. During Jokowi’s second term, the measures were gone, although the law still exists. Thus, it became ‘latent’ again in 2019 up until present. This paper claims that the Indonesian Government successfully securitised the issue in 2014 after the latent securitisation that happened in 2009. However, it remained ‘latent’ again in 2019 up until now.

Sustainable aquaculture of a protected species: The case of juvenile humphead wrasse (Cheilinus undulatus) around the Anambas Islands

Humphead wrasse (Cheilinus undulatus), also called napoleon fish or “katepas “ in Anambas Archipelago Regency, Indonesia, is a reef fish which commonly found in tropical seas. Napoleon fish exploitation is still getting higher especially in Indonesia. Nevertheless, this species had listed as a protected species by the Indonesian Government as well as enlisted in Appendix II of CITES (Convention on International Trade in Endangered Species). Following a dialog among Indonesian officials, FAO and CITES, quota permission has been given to the fisherman community of Anambas Regency. This permission was legally allowed the Anambas Fishermen to fishing the napoleon fish juveniles and reared them in floating net cages for 3-4 years to reach commercial size. About 147,000 napoleon fish were estimated to be reared in Anambas Island. The first export of Napoleon fish was recorded in 2018 by one of the Indonesian fish exporters from Anambas to Hong Kong with 1,000 fish or Rp 1 billion worth and equivalent to $ USD 71.4/kg. The aim of this research was to analyse spatial distribution, juveniles abundance and water quality of the Anambas Islands to improve the sustainability of napoleon fish juveniles resources. Juveniles and water quality data were collected during field survey in 2014 and 2015. The abundance of the juvenile was estimated from monthly data recording by fishermen and water samples were measured in-situ. Post to the measurement of the physical and chemical properties, water quality was determined by using the National Sanitation Foundation Water Quality Index (NSF-WQI) based on The Classification of the Index numerical values. The results showed that napoleon fish juveniles were concentrated in several specific locations around Anambas waters. The highest abundance of napoleon fish juvenile was observed in November and December. The waters quality indexes show good and very good conditions for culturing the juvenile in floating net cages. The success in napoleon fish juvenile rearing is a starting point to achieve the fish sustainable aquaculture-based fisheries management. This research concludes that the identified natural rearing areas of juvenile napoleon fish, good water conditions, and improved existing rearing technology might support sustainable ranching-based aquaculture of humphead wrasse in Anambas Islands waters.

Gut and intestinal biometrics of the giant trevally, Caranx ignobilis, fed an experimental diet with difference sources of activated charcoal.

Background: The giant trevally, Caranx ignobilis, is a commercially important marine fish in Indonesia. This species was initially cultured in Aceh Province. Previous reports showed that charcoal has a positive effect on survival and feed utilization of the giant trevally. However, the effects of adding charcoal to the diet on gut and intestine biometrics has, to our knowledge, never been described. Methods: Four activated charcoal sources were tested in this study using a completely randomized experimental design; coconut shell charcoal, mangrove wood charcoal, rice husk charcoal, and kernel palm shell charcoal. All treatments were performed with four replications. Juvenile giant trevally (average body weight, 16.52 ± 3.12 g; and average total length, 10.26 ± 0.64 cm) were stocked into the experimental tank at a density of 15 fish per tank. The fish were fed an experimental diet twice daily at 7 AM and 5 PM ad satiation for 42 days. Results: Analysis of variance showed that adding charcoal to the diet had significant effects on the length and width of the foveola gastrica and villous intestine (P < 0.05). The greatest length and width of the foveola gastrica was recorded in fish fed an experimental diet of rice husk charcoal with average values of 311.811 ± 9.869 µm and 241.786 ± 10.394 µm, respectively. The greatest length of intestinal villous was found in fish fed the mangrove wood charcoal diet, with a value of 135.012 ± 5.147 µm, but this length was not significantly different to that in fish fed rice charcoal and kernel palm shell charcoal. However, the greatest width of intestinal villous was recorded in fish fed the control diet (without charcoal; P < 0.05). Conclusion: The optimal sizes of the foveola gastrica and villous intestine were found in fish fed an experimental diet with rice husk charcoal.

Follow The Money Approach in The Management of Fishing Criminals by Fisheries PPNS

The many cases of Illegal Fishing, threaten the wealth of fisheries and sovereignty of Indonesia. This study aims to explain the urgency of the Follow the Money approach in handling fisheries crime cases by PPNS Fisheries. Then provide concrete recommendations for the Follow the Money implementation in handling fisheries crime cases. This paper is a normative juridical study, which is processed qualitatively. The results of this study indicate the urgency of the Follow the Money approach in handling fisheries crime cases by PPNS Fisheries due to Indonesia's large fishery wealth; the magnitude of the threat of illegal fishing in Indonesia; lack of fisheries crime cases handled by PPNS Fisheries; and the development of the modus operandi of fisheries criminals. Then, the efforts made in the Follow the Money approach are by increasing collaboration with PPATK institutions; increased cooperation with international law enforcement agencies; and the use of electronic transaction evidence as evidence at court.

Enrichment of Omega-3 from Anchovy (Stolephorus sp.) Fish Oil by Enzymatic Hydrolysis

Anchovy (Stolephorus sp.) is an economically important fish in Indonesia. Anchovy contains Omega-3 that important to maintain the health of the heart and brain. This study aimed to enrich the Omega 3 content of anchovy oil from the North Sea of West Java. The extraction of anchovy oil was carried out by the soxhlet method. Enrichment of omega 3 from anchovy fish oil is carried out by hydrolysis with a commercial lipase enzyme at concentration 500, 1000, 1500 and 2000 unit/600g fish oil, for 5, 10, 15 and 20 hour. Before hydrolysis, fish oil was added with solvent water, ethanol, toluene, and n-hexane. Omega 3 content of fish oil products were analyzed by using Gas Chromatography (GC) with FID detector with retention time 14.068 min and 15.506 min for α-Linolenat (ALA) and eicosapentaenoic (EPA), respectively. The results showed the highest omega 3 content (ALA 0.54% and EPA 1.103% ) was produced by addition n-hexane with a ratio 1:6 with the concentration of lipase was 1000 units for 20 hours.

DNA-based analysis of shark products sold on the Indonesian market towards seafood labelling accuracy program

Abstract. Abdullah A, Nurilmala M, Muttaqin E, Yulianto I. 2020. DNA-based analysis of shark products sold on the Indonesian market towards seafood labelling accuracy program. Biodiversitas 21: 1385-1390. Authentication of fishery products has relied mainly on DNA analysis of mitochondrial genes such as cytochrome c oxidase I (COI) DNA barcoding and cytochrome b (cyt b) gene fragments. The trend of sharks and rays food products trading in Indonesia significantly increased, due to their important role as protein source which may threaten the vulnerability status of some species. This study was aimed to determine the reliability of COI mini- DNA barcode and cyt b fragment for identification of shark species of heavily processed fishery products. We found the mini-DNA barcode was an effective tool to identify the shark species traded in local markets with most of the sample identifies as Carcharhinus falciformis. Our results highlight the urgency of applying DNA-based method as a routine method to control the labelling of Indonesian fish products and to manage sustainable fisheries.

MASCULINIZATION OF Betta splendens LARVAE WITH JAVA PEPPER (Piper retrofractum Vahl) EXTRACT THROUGH IMMERSION

Siamese betta fighting fish (Betta splendens) is the one of exports comodity of ornamental fish in Indonesia, but the problems of culture that fish is sex ratio of female higher than male. This research aimed to evaluate the effectiveness of java long pepper (Piper retrofractum Vahl) for betta siamese fighting fish masculinizations through larval immersion. This research was designed by randomized completely design with three treatments of different java long papper doses (0,5 mg/L, 1 mg/L, and 2 mg/L), positive control (17α-metiltestosteron 20 mg/L), and negative control with there replications for each treatments. The treatments of java long pepper doses was given to thirty larvae (D4) through immersion during 24 hours. The research showed that java long pepper extract with dose 2 mg/L obtained the higher male ratio (59,82%) compared with dose 0,5 mg/L (45,11%), 1 mg/L (53,92%), and negative control (23,23%). Java long pepper extract with dose 2 mg/Lincreased the male ratio 36,59% compared with negative control. Java long pepper extract have no effect for survival rate of siamese betta fighting larvae during cultured.

KEBIJAKAN PEMBERANTASAN ILLEGAL FISHING DI ZONA EKONOMI EKSKLUSIF INDONESIA LAUT CINA SELATAN TAHUN 2017

There have been many changes from time to time in fish resources in the waters of the South China Sea. These changes are caused by irresponsible people who carry out illegal fishing or commonly called illegal, unreported and unregulated fishing (IUU-fishing). Handling and eradication of illegal fishing will support the targets needed in economic development programs maritime based. In addition, illegal fishing in an exclusive economic zone, specifically in the South China Sea, not related to fishing will have an impact on losses, moreover more worrying is the matter of the Republic of Indonesia's sovereignty at stake. Not being able to eradicate and provoke illegal means that the dignity and national dignity in the eyes of the international community will be even worse. The government needs to improve and improve the oversight problem that controls fish resources in Indonesian fisheries by foreign vessels and national fishing vessels. In addition, the Ministry of Maritime Affairs and Fisheries needs to formulate steps set out in the rules and eradicate illegal fishing practices. Based on this description, there are two questions that will be answered in this study, namely: (1) What is the policy and coordination system between government institutions in combating illegal fishing in Indonesia's Exclusive Economic Zone, especially in the South China Sea? (2) Why is the practice of illegal fishing in Indonesia's Exclusive Economic Zone, specifically in the South China Sea difficult to overcome, and what are its weaknesses? Where this research uses qualitative methods, which consist of writings either books, journals, or mass media. And can also consist of words and writings from people who are close intact, in other words the data include descriptive data.

Neobenedenia girellae infestation on cobia (Rachycentron canadum) in Hurun Bay Lampung, Indonesia

Cobia (Rachycentron canadum) is newly developed fish in Indonesia with an export value, however, the production activities of this fish continue to decrease due to fish massive mortality caused by disease. This study aimed to determine the predilection, prevalence, and intensity of Neobenedenia girellae infestation on cobia in floating net cages culture at Hurun Bay, Lampung. The sampling method used in this study was the purposive sampling method. Fish samples were taken at 20-30 cm as much as 50 fish, while 40-50 cm as much as 20 fish. Neobenedenia girellae were found on cobia eyes, head, and fins. Results showed the prevalence level in 20-30 cm fish was 30% and intensity level was 2.31 parasites/fish, while in 40-50 cm fish showed the prevalence level of 65% with the intensity of 1.47 parasites/fish.

The spermatozoa viability of kancra fish (Tor soro, Valenciennes 1842) 48-hour after freezing: effect of brown sugar as natural cryoprotectant

Kancra fish (Tor soro, Valenciennes 1842) is one of the endemic fish in Indonesia which population keeps decreasing due to degradation of the environment. Conservation is needed and cryopreservation is an effective strategy in this regard. Brown sugar as a natural cryoprotectant has the potential to substitute less eco-friendly synthetic cryoprotectant. The study was carried out to determine the viability of T. soro spermatozoa after 48 hours of cryopreservation using brown sugar. Sperm sample were collected through stripping method. The ejaculated sperm were diluted using the extender (brown sugar-fish ringer + methanol 10%, 1:9). The brown sugar concentration examined were 0%, 5%, 10%, 15%, 20%, and 25%, and the sample was equilibrated at 4 °C for 10 minutes, and frozen at -10 °C for 48 hours. The process was followed by thawing process ast 40 ºC for 60 seconds. Data were analyzed using ANOVA, followed by Tukey test. The results showed that brown sugar concentration of 15% significantly affects viability of the sperm after 48 hours of cryopreservation with 83.75±1.71% (p<0.05). However, a study is needed to determine the effectivity of brown sugar as a cryoprotectant.