PRESENCE, DISTRIBUTION, MIGRATION PATTERNS AND BREEDING SITES OF THIRTY FISH SPECIES IN THE AYEYARWADY SYSTEM IN MYANMAR

WIN KO KO2, ZI ZA WAH2, Norberto ESTEPA3, OUCH Kithya1

SARAY Samadee1, KHIN MYAT NWE2, Xavier TEZZO1, Eric BARAN1

1 WorldFish 2 Myanmar Department of Fisheries, 3 Consultant

TABLE OF CONTENTS 1 INTRODUCTION ...... 1 2 METHODOLOGY ...... 1 2.1 Approach ...... 1 2.2 Area studied ...... 2 2.1 Surveys of fishermen ...... 3 2.1 Species selection ...... 3 2.2 Data analysis ...... 7 2.3 Ecological value of townships ...... 8 2.3.1 Number of species breeding by township ...... 8 2.3.2 Importance of species to fisheries ...... 8 2.3.3 Surface area of fish breeding sites by township ...... 9 2.3.4 Ecological value from a fishery perspective ...... 9 2.4 LIMITATIONS AND POSSIBLE BIASES OF THE STUDY ...... 10 2.4.1 Self-assessment of yield ...... 10 2.4.2 Variable fishing effort ...... 10 3 RESULTS...... 11 3.1 Species whose migratory status is unknown ...... 11 3.2 Overview of migration and breeding in the Ayeyarwady system ...... 11 3.3 Species by zone and habitat type ...... 15 3.4 Seasonal abundance of fish surveyed ...... 15 3.5 Timing of catches ...... 17 3.6 Species and number of breeding sites ...... 17 3.7 Breeding sites in townships ...... 17 3.8 Ecological value of townships in fisheries ...... 19 4 CONCLUSION ...... 21 5 BIBLIOGRAPHY ...... 22 6 ANNEX 1: MONTHLY DISTRIBUTION OF YIELDS ...... 25 7 ANNEX 2: DETAILS BY MIGRATORY SPECIES SURVEYED ...... 27 7.1 Migratory species with no known breeding sites ...... 27 Hilsa kelee ...... 27 Ilisha megaloptera ...... 29 7.2 Non-migratory species with breeding sites ...... 30 Bagarius bagarius ...... 30 Cirrhinus mrigala ...... 31 Gudusia variegata ...... 32 Hemibagrus microphthalmus ...... 33 Pangasianodon gigas ...... 34 Sperata aor ...... 35 7.3 Migratory species with breeding sites ...... 36 Catla catla ...... 36 Cirrhinus cirrhosus ...... 41 Labeo calbasu...... 46 Lates calcarifer ...... 49 Pangasius conchophilus ...... 52 Pangasius pangasius ...... 57 Rita rita ...... 62 Silonia silondia ...... 67 Wallago attu ...... 70

EXECUTIVE SUMMARY

Our study of the presence, distribution, migration patterns and breeding sites of thirty fish species in the Ayeyarwady system is based on a systematic sampling of traditional ecological knowledge. More than 200 fishers were interviewed in 42 sites belonging to 37 townships in the delta and the Central Dry Zone.

Thirty species were selected for surveys, in addition to hilsa, which was dealt with in a separate companion report. This selection was based on a combination of criteria covering commercial importance, migratory status in other countries, and critically endangered status for some species.

The migratory status of fourteen fish species out of 30 is not known to fishermen. These species are: Anguilla anguilla and Anguilla bicolor (caught but not abundant), Anodontostoma chacunda, Bagarius yarrelli, Chaca burmensis, Macrognathus zebrinus, Pangasianodon hypophthalmus, Pangasius larnaudii, Raiamas guttatus, Tenualosa toli and Pristis microdon (rare species). The migratory status is also unknown for Cyclocheilichthys apogon, Mastacembelus armatus and Monopterus cuchia, although these species are not particularly rare.

For the other species, average monthly catch per fisherman is much higher in the delta than in the Central Dry Zone. The five migratory species dominant in catches are Pangasius conchophilus, Tenualosa ilisha, Rita rita, Pangasius pangasius and Hemibagrus microphthalmus. Three out of five are catfishes. These top-five species are followed by species that are not abundant but remain common, in particular during their migration period: Wallago attu, Cirrhinus cirrhosus/mrigala, Bagarius bagarius, Catla catla, Labeo calbasu, Sperata aor, and Silonia silondia. The remaining species (Gudusia variegata, Lates calcarifer, Bagarius yarrelli, Hilsa kelee, Ilisha megaloptera, Macrognathus zebrinus, Pangasianodon hypophthalmus and Mastacembelus armatus) are rare in catches. The monthly abundance patterns of these species are detailed in the report.

Among these species, two are considered to be migratory with no known breeding sites (Hilsa kelee and Ilisha megaloptera). Six species are considered non-migratory, but their breeding sites in the Ayeyarwady system are known (Bagarius bagarius, Cirrhinus mrigala, Gudusia variegata, Hemibagrus microphthalmus, Pangasianodon gigas, Sperata aor). Last, there are nine migratory species whose breeding sites are also known (Catla catla, Cirrhinus cirrhosus, Labeo calbasu; Lates calcarifer; Pangasius conchophilus; Pangasius pangasius; Rita rita; Silonia silondia; Wallago attu). We map in the report all the breeding areas described by fishers for these species.

The present study also features an analysis of zones based on their ecological value from a fisheries protection perspective. This ecological value is a combination of number of species breeding, surface area of breeding sites, and importance of species to fisheries. Results show that Hinthada Township features the highest ecological value, with large spawning sites for 9 species, most of them being commercially valuable. The townships that feature the second highest ecological value are Ingapu, Myanaung, Yandoon, and Twantay. Nine townships - Hainggyi, Kyaiklat, Labutta, Mandalay, Myingyan, Ngapudaw, Pathein, and Pyinzalu- feature no breeding sites and therefore have low ecological value. 1 INTRODUCTION This report details the presence, spatial-temporal distribution, size, migration patterns and breeding sites of thirty fish species in the Ayeyarwady system in Myanmar. This study is based on local ecological knowledge and the experience of fishers in each township.

This study complements a previous report on distribution and migration patterns and breeding sites of Hilsa (Tenualosa ilisha) in the same zones, i.e. Ayeyarwady Delta and Central Dry Zone (Baran et al. 2015). Both studies aim at providing the Department of Fisheries with information relevant to the management of migratory fish resources of significance to fisheries or conservation, for the sustainability of these species.

2 METHODOLOGY 2.1 Approach The study’s approach is based on local or traditional ecological knowledge (TEK), as developed and promoted by Johannes (1981), Johannes et al. (2000), Rahman (2000) or Moller et al. (2004). Concepts and methodologies for the use of TEK in tropical fisheries assessments were developed by Johannes et al. (1989) and Haggan et al. (2003). Comparison of findings originating from local ecological knowledge questionnaires and from catch data were tested by Poizat and Baran (1997) and Ticheler et al. (1998). These authors conclude that fishers have a reliable knowledge of fish spatio-temporal patterns, and exploiting this knowledge allows screening a large amount of information at a limited cost and can provide reliable bases for more detailed or targeted assessments. Ecological assessments based on fishers’ knowledge were largely used in the Mekong (Chhuon Kim Chhea 2000, Baird and Overton 2001, Dubois 2005, Baird 2007, Chan Sokheng et al. 2008, Baran and Seng Sopheak 2011). Using fishers’ knowledge was in particular at the center of a large-scale project implemented by the Mekong River Commission (Poulsen et al. 2000, Valbo-Jørgensen and Poulsen 2000, Bao et al. 2001). That MRC project resulted in a reference identification and mapping of fish migrations throughout the Mekong Basin.

The methodology used for the present study is largely derived from the methodology developed for the Mekong River Commission (Poulsen and Valbo-Jørgensen 1999; Poulsen et al. 2000). It was simplified to some extent since this study does not involve many species, nor systematic GIS mapping, nor market surveys. The methodology is detailed in Baran et al. (2015).

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2.2 Area studied The study area covers the Ayeyarwady Delta and extends up to Katha on the Ayeyarwady mainstream, and up to Kalewa on the Chindwin River. This study area was chosen because Hilsa had been reported up to Mandalay (Johnstone et al. 2013), and because fishers in Mandalay mentioned the presence of Hilsa in the Chindwin River.

The rivers surveyed and the study sites are illustrated in Figure 1.

Figure 1: Rivers surveyed and sites surveyed in the Ayeyarwady system

Forty-two sites within 37 townships covering all the major rivers of the delta (Figure 2) and the main rivers of the Central Dry Zone (Figure 3) were surveyed between December 2013 and December 2014. The total number of sites selected is based on a trade-off between an extensive coverage of the delta and the budget available. The survey was conducted only once in each site. It did not have to be seasonally repeated since fishers reported generic annual migration patterns and locations of breeding sites that do not substantially change over years.

The information collected was entered using digital tablets so that errors in transcribing can be reduced (Tezzo et al. 2014).

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Figure 2: Study sites in the Ayeyarwady Delta Figure 3: Study sites in the Central Dry Zone

2.1 Surveys of fishermen In each site, the survey was organized through the local Department of Fisheries (DoF). Fishers interviewed were selected based on a minimum of 10 years of fishing experience and 5 years of residence in the site surveyed. Each interviewee received USD 5 to cover time and transportation costs to the survey site. Each interview was conducted with a panel of 5 to 8 fishers, and over 200 fishers were surveyed for the entire study. The questionnaire can be found in Annex 4. When fishers disagreed, the consensus response agreed by most participants was recorded.

2.1 Species selection Initially, three specialists from the Department of Fisheries in Yangon selected 30 species as commercially important. In parallel, we used a file of 103 migratory species in the Mekong (Ziv et al. 2012); this latter list was combined with the list of Ayeyarwady species (www.fishbase.org), which allowed identifying 65 migratory (Mekong) species also found in the Ayeyarwady River. The lists of commercially important and migratory species in the Ayeyarwady were combined. Each species was then reviewed in relation to i) abundance (importance in fisheries); ii) protection needs (conservation status); iii) known spawning sites; iv) ease of identification, and v) special interest (unique or iconic species). Each species was given a rating of 0, 1, or 2 for each of the five criteria. Ultimately, the 42 species with ratings superior to zero were selected. After testing of questionnaires, and for feasibility reasons, a final list of 31 priority species was kept for full scale surveys (30 species + Hilsa).

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Thus, this list combines known migratory species (e.g. Pangasianodon gigas), species abundant in catches (e.g. Cyclocheilichthys apogon) and rare or critically endangered species (e.g. the sawfish Pristis microdon).

Table 1: Survey places and townships nᵒ Places Townships nᵒ Places Townships 1 Bogale Bogale 24 Monyo Monyo 2 Danubyu Danubyu 25 Monywa Monywa 3 Dedaye Dedaye 26 Myanaung Myanaung 4 Hinthada Hinthada 27 Myangmya Myangmya 5 Htantabin Htantabin 28 Myingyan Myingyan 6 Ingapu Ingapu 29 Myinmu Myinmu 7 Kalewa Kalewa 30 Ngapudaw Ngapudaw 8 Katha Katha 31 Hiainggyi 9 Kyaiklat Kyaiklat 32 Ngathaingchaung Yegyi 10 Kyangin Kyangin 33 Pakokku Pakokku 11 Kyauktan Kyauktan 34 Pathein Pathein 12 Sit Taung 35 Pyapon Pyapon 13 Kyaik Hto 36 Pyay Pyay Kyaik Hto 14 Thein Za Yet 37 Thabaung Thabaung 15 Sut Pa Nu 43 Thanatpin Thanatpin 16 Pyinzalu 38 Twantay Twantay Labutta 17 Labutta 39 Wakema Wakema 18 Lemyethna Lemyethna 40 Kyonemangay 19 Magway Magway 41 Yandoon Yandoon 20 Mandalay Mandalay 44 Waw Waw 21 Maubin 42 Zalun Zalun Maubin 22 Shwe Taung Hmaw 23 Mawgyun Mawgyun

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BOX 1: CONNECTION BETWEEN SALWEEN RIVER AND AYEYARWADY RIVER

During the interview in the Delta, fishermen said that Tenualosa ilisha would come in high quantities from the Salween Delta and nearby coastal zone. For this reason, we surveyed four additional sites-Kyaik Hto, Sit Taung, Sut Pa Nu, and Thein Za Yat- in the Salween system. As a result, breeding sites of four species –Lates calcarifer, Pangasius pangasius, Tenualosa ilisha, and Wallago attu were identified.

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Figure 4: Water depth in Ayeyarwady River. Source: excerpt of an International Chart Series navigation map.

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2.2 Data analysis During the interview, abundance data were expressed in “viss”, the local weight unit used by all fishers (1 viss=1.6 kg), then converted into kilograms during analysis. These values reflect the data from the past year, and integrate the catch variability among the different fishers taking part in each interview. The year starts in January, although many fishers in the delta consider August (after the monsoon) to be the fishing season start.

During interviews, averaging was necessary when fishers stated that two size classes were caught within a given month. In such cases, the two fish size classes were plotted for that month (green triangle and red square; Figure 5) on the histogram of fish sizes, and the fish icon size was adjusted to the average distance between these two points. The drawback of this graphical representation is that two size classes are represented by one fish only, but representing two fish classes per month would have been graphically unreadable. The direction of the fish represents the direction of migration. When this direction is unknown, it is represented by a question mark, yet the fish icon is placed upwards, which might also influence the reading.

Figure 5: How fish sizes are plotted and illustrated by a fish icon

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2.3 Ecological value of townships The ecological value of townships in the Ayeyarwady system is mapped based on the number of species that breed there, their importance to fisheries the area of breeding sites.

The mapping is done for the townships of the Ayeyarwady Delta and Central Dry Zone. The number of townships considered is limited to those that border the Ayeyarwady River and its branches in the Delta. This represents 37 townships (townships outside the Ayeyarwady system were not mapped here).

For each township, an index of ecological value from a fishery perspective is calculated. Three elements contribute to the calculation of that index:

1. Number of species breeding by township 2. Importance of species to fisheries 3. Surface area of fish breeding sites by township

2.3.1 Number of species breeding by township An index value is given to each township depending on the number of species breeding in that township: Number of breeding species Index 0 species 0 1 to 3 species 1 4 to 6 species 2 7 to 9 species 3

2.3.2 Importance of species to fisheries These surveys showed that out of the 31 species surveyed (see section 3.3), 15 are not considered present or having breeding sites in the study zone. Finally, the sixteen fish species with breeding sites in the Ayeyarwady Delta and Central Dry Zone were identified. These species include: Bagarius, Catla, Cirrhinus cirrhosus, Cirrhinus mrigala, Gudusia variegata, Hemibagrus microphthalmus, Labeo calbasu, Lates calcarifer, Pangasianodon gigas, Pangasius conchophilus, Pangasius, Rita, Silonia silondia, Sperata aor, Tenualosa ilisha and Wallago attu.

The species were ranked by three Myanmar fisheries specialists according to their importance in fisheries, and given a score ranging from 0 to 2 from the least to the most important. Species Score A Species Score A Bagarius bagarius 1 Pangasianodon gigas 1 Catla catla 2 Pangasius conchophilus 0 Cirrhinus cirrhosus 1 Pangasius pangasius 1 Cirrhinus mrigala 1 Rita rita 0 Gudusia variegata 2 Silonia silondia 1 Hemibagrus microphthalmus 1 Sperata aor 1 Labeo calbasu 1 Tenualosa ilisha 2 Lates calcarifer 2 Wallago attu 1

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In each township, the sum of above scores for the species found was calculated. The sum was then classified into four categories:

Total score of each township Score B 0 0 1 to 8 1 9 to 17 2 18 to 24 3

2.3.3 Surface area of fish breeding sites by township The surface area of breeding sites in each township was measured on Google Earth based on the paper maps drawn during the field study. The surface area was classified into four categories:

Surface area of breeding site (ha) Score C 0 0 1 to 19,999 1 20,000 to 39,999 2 40,000 to 59,999 3

2.3.4 Ecological value from a fishery perspective The final index of each township was the sum of 3 indexes above. This sum index ranged from 0 to 8, and was split into 6 main categories:

Sum of score Class Description 0 1 Each score = 0 3 2 Each score = 1 4 3 Two scores = 1, one score = 2 5 4 Two scores = 2, one score = 1 6 5 At least two scores = 2 or 3 8 6 Two scores = 3, one score = 2

For example, township X with 1 to 3 species -> score A = 1; Importance of these species to fisheries -> score B = 1; surface area of breeding sites -> score C = 2; sum = 1+1+2 = 4 - > township X belongs to class 3.

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2.4 LIMITATIONS AND POSSIBLE BIASES OF THE STUDY 2.4.1 Self-assessment of yield The validity of self-assessment of catch per month, as reported by fishers during interviews, was not tested during the course of this study. However, the data is believed to be relatively accurate because: i) answers were anonymous, and catches are not subject to taxes per kilo (it is the gears that are taxed); ii) questions are about the average daily catch each month, which does not require integration nor calculation; and iii) experience in the Mekong shows that weight estimates among fishers’ households are quite precise (Garrison et al. 2006). Furthermore, the present study is not focused on absolute yields, but on a comparison of locations and on relative patterns. Therefore, under the assumption that the bias is constant, the comparisons remain valid.

2.4.2 Variable fishing effort The quantity caught is a combination of fish density and fishing gear used; it reflects not only the fish abundance but also the dominant fishing gear – and their size – in a given area. Since the fishing capacity per fisher is not constant throughout the study (fishers by the sea tend to be more professional and have more equipment), the variable fishing effort is an uncontrolled variation factor between surveys, and may bias the comparison of catches throughout the study area.

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3 RESULTS 3.1 Species whose migratory status is unknown The 200 fishermen interviewed do not know the migratory status of 14 species; most of these species are quite rare and have no known breeding sites in the places surveyed. These species are detailed below.

Anguilla anguilla is known to fishermen in 24 townships. In 96% of the townships, fishermen interviewed did not know its migratory status. It is a rare species with only a few individuals caught per year. Anguilla bicolor bicolor is known to fishermen in 11 townships. It is also considered rare. Anodontostoma chacunda is known to fishermen in 3 townships. This species is considered very rare. Bagarius yarrelli is known to fishermen in 19 townships. It is rare, with only one or two fish caught per year. Chaca burmensis is known to fishermen in 19 townships. It is considered rare with less than 5 fish caught per year. Cyclocheilichthys apogon is known to fishermen in 22 townships; it is not particularly rare but none of the fishermen interviewed knew about its migratory status. Macrognathus zebrinus is well known to fishermen in 32 townships, but none of these fishermen knew its migratory status. A similar pattern is found with Mastacembelus armatus (known in 27 townships) and Monopterus cuchia (known in 30 townships). Pangasianodon hypophthalmus is known by fishermen in 14 townships, of which 93% did not know its migration status. This species is considered rare, with only 1 or 2 found per year. Pristis microdon, a critically endangered species, has never been met by any fishermen surveyed. Pangasius larnaudii is found in 9 townships. This species is considered rare, with less than 5 found per year. Raiamas guttatus is found in 19 townships. This species is also considered quite rare. Last, Tenualosa toil is known in 7 townships, with only one or two fish found per year. Like all above species, fishermen do not know its migratory status. The monthly abundance pattern and geographical distribution of these species are not detailed in the present report focused on migratory species.

It is surprising to see that two eels (Anguilla anguilla and Anguilla bicolor), well known catadromous species with significant catches in Myanmar, are not considered migratory by fishers. The fact that fishers do not know about migratory patterns of some species also reflect the rarity or very limited abundance of these species in the area surveyed, as illustrated by the quasi-extinct sawfish Pristis microdon.

3.2 Overview of migration and breeding in the Ayeyarwady system The findings detailed in Annex 2 are summarized in the table below.

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Table 2: Overview of migration and breeding in the Ayeyarwady system

Species Migration and/or distribution Breeding sites Bagarius No information Breeding sites along Ayeyarwady River in Pyay Township Biggest breeding site in Pyay Township Breeding season: March to April Catla catla Upstream migration of big fishes (around 20 inches) in the Breeding sites along 4 rivers (Chindwin, Ayeyarwady, Pathein and Delta (September to November and in the CDZ (February - Toe) in Kalewa, Kyangin, Myanaung, Monyo, Ingapu, Hinthada, April and September - December). Downstream migration Zalun, Danubyu, Yandoon, Twantay, Ngathaingchaung, and Wakema of small fishes (10 inches). Townships Highest yield in Twantay (135 kg/day/fisher in September); Biggest breeding site in Ingapu along Pathein River lowest in Mawgyun (< 5 kg/day/fisher in November). Breeding season: May to August Cirrhinus cirrhosis Upstream migration of big and small fishes in the Delta Breeding sites along 3 rivers (Ayeyarwady, Pathein, and Toe) in and the CDZ (January - May and September- December). Ingapu, Myanaung, Danubyu, Zalun, Yandoon, Twantay and Downstream migration of 20 inches individuals in April - Ngathaingchaung Townships. May. Biggest breeding site: in the floodplains along Pathein river in Highest yield in Myinmu (45 kg/day/fisher in November); Ingapu. lowest in Maubin and Dedaye (5 kg/day/fisher). Breeding season: May to June. Cirrhinus mrigala No information Breeding sites along 2 rivers (Ayeyarwady River, and Pathein River) in Hinthada, Ingapu, Kalewa, Katha, and Monyo Township Biggest breeding site in Ingapu along Pathein River Breeding season: March to July Gudusia variegata No information Breeding site along Ayeyarwady River in Hinthada Township Biggest breeding site in Hinthada along Ayeyarwady River Breeding season: March to April Hemibagrus No information Breeding sites along 2 rivers (Ayeyarwady River and Pathein River) microphthalmus in Ingapu, Myanaung, and Myinmu Townships Biggest breeding site in Ingapu along Pathein River Breeding season: June to July

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Species Migration and/or distribution Breeding sites Hilsa kelee Upstream migration of small and big fishes in the Delta No information (January - June and September – December) and in the CDZ (October - November). Highest yield in Wakema (8 kg/day/fisher); lowest in Kyangin (5 kg/day/fisher). Ilisha megaloptera Upstream migration in the Delta (April - August). Highest No information yield in Bogale (30 kg/day/fisher in August); lowest in Mawgyun (< 3 kg/day/fisher). Labeo calbasu Upstream migration of juveniles and big fishes in the Delta Breeding sites along 4 rivers (Ayeyarwady, Chindwin, Pathein and (January, May, and October) and in the CDZ (April - June Toe) in Katha, Kalewa, Pakokku, Ingapu, Myanaung, Hinthada, and August - November). Highest yield in Ingapu (25 Maubin, and Yandoon Townships. kg/day/fisher in September); lowest in Kyangin (< 1 Biggest breeding site in the floodplains along Pathein river in Ingapu. kg/day/fisher between April and June). Breeding season: June to February Lates calcarifer Upstream migration of small and big fishes in September – Breeding sites along 8 rivers (Toe River, Donyan River, Pyapon River, January. Highest yield in Wakema (115 kg/day/fisher in Myngagon River, Ayeyarwady River, Bogale River, Kyondon River, November); lowest in Pyapon (1 kg/day/fisher in and Salween River) in Bogale, Dedaye, Kyaik Hto, Mawgyun, Pyapon, November). Thanatpin, and Waw Townships. Biggest breeding site in Dedaye along Toe River. Breeding season: May to June Pangasius conchophilus Upstream migration of adult fishes in the Delta (January - Breeding sites along 3 rivers (Toe River, Ayeyarwady River, and May and September - November) and in the CDZ Yangon River) in Kyangin, Kyauktan, Twantay, and Yandoon (September - December, and February - April). Townships. Highest yield in Kyangin (200 kg/day/fisher in October); Biggest breeding site in the floodplains Twantay along Toe River lowest in Pakokku (2 kg/day/fisher in April). Breeding season: May to August

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Species Migration and/or distribution Breeding sites Pangasius pangasius Upstream migration of 15-20 inches fishes in the Delta Breeding sites along 4 rivers (Pyapon River, Ayeyarwady River, (January - April and October - December) and in the CDZ Yangon River, Salween River) in Hinthada, Htantabin, Myanaung, (February - November, except June). Kyaik Hto, Twantay, and Pyapon Township Highest yield in Twantay (120 kg/day/fisher in November); Biggest breeding site: mainstream of Pyapon River in Pyapon. lowest in Myingyan (3 kg/day/fisher). Breeding season: December to June Pangasianodon gigas No information Breeding site in the junction of Toe River and Twantay Canal in Twantay Township. Biggest breeding site in Twantay Township Breeding season: no information Rita rita Upstream migration in the Delta (March - December) and Breeding sites along 2 rivers (Ayeyarwady River, and Pathein River) in the CDZ (January - April, and October - December). in Pyay, Myanaung, Zalun, and Thabaung Townships. Highest yield in Kyangin (300 kg/day/fisher in October); Biggest breeding site along Ayeyarwady River in Pyay. lowest in Mawgyun (< 1 kg/day/fisher). Breeding season: March and October Silonia silondia Upstream migration of 15-20 inches fishes in the Delta Breeding sites along Ayeyarwady River in Hinthada, Yandoon, and (January - March and between September - December) Maubin Townships. and in the CDZ (September - October). Biggest breeding site in Hinthada along Ayeyarwady River Highest yield in Ingapu (15 kg/day/fisher in September); Breeding season: May to June. lowest in Patheingyi (1 kg/day/fisher). Sperata aor No information Breeding sites along Ayeyarwady River in Hinthada, and Zalun Townships Biggest breeding site in Hinthada along Ayeyarwady River Breeding season: April to May Wallago attu Upstream migration of young and adult fishes in the Delta Breeding sites along 5 rivers (Ayeyarwady, Myngagon, Pathein, Toe (January - March and between September - December) and Salween Rivers) in Katha, Kalewa, Myinmu, Pakokku, Kyaik Hto, and in the CDZ (January - April and October - December). Kyangin, Myanaung, Ingapu, Thabaung, Hinthada, Maubin, Twantay, Highest yield in Myinmu (120 kg/day/fisher in November); Mawgyun, Zalun, Yandoon, and Waw Townships. lowest in Pakokku (2 kg/day/fisher in March). Biggest breeding site in Myngagon and the lower part of Ayeyarwady in Mawgyun. Breeding season: May to July

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3.3 Species by zone and habitat type We summarize below how species use different habitats in different zones

Table 1. Species by zone, habitat type and river

Zone Habitat type Habitat name Species observed Cirrhinus cirrhosus/mrigala; Hemibagrus Ayeyawady River microphthalmus; Labeo calbasu; Sperata aor; Central Tenualosa ilisha; Wallago attu Dry River Catla catla; Cirrhinus cirrhosus/mrigala; Zone Chindwin River Labeo calbasu; Tenualosa ilisha; Wallago attu Bogale River Lates calcarifer Flood Plains Toe River Lates calcarifer Pyapon Township Lates calcarifer Paddy Field Toe River Lates calcarifer Bagarius bagarius; Catla catla; Cirrhinus cirrhosus/mrigala; Gudusia variegata; Hemibagrus microphthalmus; Labeo calbasu; Ayeyawady River Pangasius conchophilus; Pangasius pangasius; Rita rita; Silonia silondia; Sperata aor; Tenualosa ilisha; Wallago attu Catla catla; Cirrhinus cirrhosus/mrigala; Hemibagrus microphthalmus; Labeo calbasu; Delta Nga Wann River Pangasius pangasius; Rita rita; Silonia River silondia; Sperata aor; Tenualosa ilisha; Wallago attu Catla catla; Cirrhinus cirrhosus/mrigala; Labeo calbasu; Pangasius conchophilus; Toe River Pangasius pangasius; Silonia silondia; Tenualosa ilisha; Wallago attu Yangon River Pangasius conchophilus; Tenualosa ilisha Lates calcarifer; Tenualosa ilisha; Wallago Yarzudaing River attu Ywe River Tenualosa ilisha River Bank Pyapon River Catla catla; Pangasius pangasius

3.4 Seasonal abundance of fish surveyed The questionnaires about fish yield per month and per fisherman in each township allow plotting an overview of dominant species in fisheries (Figure 6). This figure is based on tables of Annex 1.

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Figure 6. Monthly distribution of yield in kg per fisherman and per day in the Ayeyarwady Delta (left) and in the Central Dry Zone (right). Data plotted represent the average of all townships in each zone.

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3.5 Timing of catches We present in the table below the timing of catches for the various species surveyed.

Table 3. Number of townships in which a given species is caught at a given time of the day

Species name Early Day time Evening Night time morning Anguilla anguilla 1 Bagarius bagarius 5 Bagarius yarrelli 3 Catla catla 16 16 Cirrhinus cirrhosus /mrigala 19 19 Gudusia variegata 1 Hemibagrus microphthalmus 4 Hilsa kelee 2 Ilisha megaloptera 2 2 Labeo calbasu 8 8 Lates calcarifer 7 Macrognathus zebrinus 2 Mastacembelus armatus 1 1 Pangasianodon hypophthalmus 1 Pangasius conchophilus 16 16 Pangasius pangasius 18 18 18 Rita rita 15 15 Silonia silondia 6 6 Sperata aor 5 5 Tenualosa ilisha 30 30 30 Wallago attu 14 14 14

3.6 Species and number of breeding sites Two species are characterized by a high number of breeding sites in multiple townships; these species are Tenualosa ilisha (hilsa) and Wallago attu (whiskered catfish). Conversely, six species are characterized by a very limited number of known breeding sites (1 to 3 maximum). These species are:  Bagarius bagarius, Gudusia variegata and Pangasianodon gigas (one breeding site)  Sperata aor (two breeding sites)  Hemibagrus microphthalmus and Silonia silondia (three breeding sites) These six species require special attention in terms of management through the protection of their breeding sites. Hinthada in particular is a township where three of these species breed.

3.7 Breeding sites in townships We detail below the number of breeding sites in each township surveyed, for the target species.

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Table 4: Breeding sites of 16 species in 42 townships. Kyonemangay was distinguished from Wakema, and the four townships outside the Ayeyarwady system are added here.

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3.8 Ecological value of townships in fisheries Hinthada Township features the highest ecological value from a fishery perspective (index = 5 = exceptional), with spawning sites for 9 species -these 9 species being considered all important to fisheries- and at least 28,000 ha of breeding sites.

The townships that feature the second highest ecological value (index = 4 = very high) are Ingapu, Myanaung, Yandoon, and Twantay Townships. These four townships include breeding sites for 7 to 8 species –most of these species being important to fisheries. However, the size of the breeding sites in these four townships varies between 1,000 and 8,000 ha, which is much smaller than in Hinthada.

The third highest ecological value townships (index = 3 = high) are Dedaye, Kalewa, Kyangin, Maubin, and Zalun. Despite bordering Hinthada, a township of exceptional value, the Zalun township is characterized by a small surface area of breeding sites (2300 ha).

Bogale and Mawgyun Townships feature a medium ecological value (index = 2 = medium).

The fifth highest ecological value townships (index = 1 = low) include: Danubyu, Htantabin, Katha, Kyauktan, Kyonemangay, Lemyethna, Magway, Monyo, Monywa, Myangmya, Myinmu, Yegyi, Pakokku, Pyapon, Pyay, Shwe Taung Hmaw, Thabaung, and Wakema. Danubyu is surrounded by townships of medium to high ecological value; however, this township has spawning sites for only two species, and a small area of breeding sites. Lemyethna Township, although it borders Hinthada, features a very small spawning ground with only one species known to breed there.

Nine townships - Hainggyi, Kyaiklat, Labutta, Mandalay, Myingyan, Ngapudaw, Pathein, and Pyinzalu- feature no breeding sites and has an ecological value considered insignificant (index = 0). Kyaiklat Township is surrounded by townships with a medium ecological value ranging from 1 to 3; however Kyaiklat, unlike the others, does not features any breeding site.

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Figure 7: Ecological value of townships in the Central Dry Zone from a fish resource protection perspective

Figure 8: Ecological value of townships in the Ayeyarwady Delta from a fish resource protection perspective 20 |

4 CONCLUSION Our study of the presence, distribution, migration patterns and breeding sites of thirty fish species in the Ayeyarwady system is based on a systematic sampling of traditional ecological knowledge. More than 200 fishers were interviewed in 42 sites belonging to 37 townships in the delta and the Central Dry Zone.

Thirty species were selected for surveys, in addition to hilsa, which was dealt with in a separate companion report. This selection was based on a combination of criteria covering commercial importance, migratory status in other countries, and critically endangered status for some species.

The migratory status of fourteen fish species out of 30 is not known to fishermen. These species are: Anguilla anguilla and Anguilla bicolor (caught but not abundant), Anodontostoma chacunda, Bagarius yarrelli, Chaca burmensis, Macrognathus zebrinus, Pangasianodon hypophthalmus, Pangasius larnaudii, Raiamas guttatus, Tenualosa toli and Pristis microdon (rare species). The migratory status is also unknown for Cyclocheilichthys apogon, Mastacembelus armatus and Monopterus cuchia, although these species are not particularly rare.

For the other species, average monthly catch per fisherman is much higher in the delta than in the Central Dry Zone. The five migratory species dominant in catches are Pangasius conchophilus, Tenualosa ilisha, Rita rita, Pangasius pangasius and Hemibagrus microphthalmus. Three out of five are catfishes. These top-five species are followed by species that are not abundant but remain common, in particular during their migration period: Wallago attu, Cirrhinus cirrhosus/mrigala, Bagarius bagarius, Catla catla, Labeo calbasu, Sperata aor, and Silonia silondia. The remaining species (Gudusia variegata, Lates calcarifer, Bagarius yarrelli, Hilsa kelee, Ilisha megaloptera, Macrognathus zebrinus, Pangasianodon hypophthalmus and Mastacembelus armatus) are rare in catches.

Among these species, two are considered to be migratory with no known breeding sites (Hilsa kelee and Ilisha megaloptera). Six species are considered non-migratory, but their breeding sites in the Ayeyarwady system are known (Bagarius bagarius, Cirrhinus mrigala, Gudusia variegata, Hemibagrus microphthalmus, Pangasianodon gigas, Sperata aor). Last, there are nine migratory species whose breeding sites are also known (Catla catla, Cirrhinus cirrhosus, Labeo calbasu; Lates calcarifer; Pangasius conchophilus; Pangasius pangasius; Rita rita; Silonia silondia; Wallago attu). We map in the report all the breeding areas described by fishers for these species.

The present study also features an analysis of zones based on their ecological value from a fisheries protection perspective. This ecological value is a combination of number of species breeding, surface area of breeding sites, and importance of species to fisheries. Results show that Hinthada Township features the highest ecological value, with large spawning sites for 9 species, most of them being commercially valuable. The townships that feature the second highest ecological value are Ingapu, Myanaung, Yandoon, and Twantay. Nine townships - Hainggyi, Kyaiklat, Labutta, Mandalay, Myingyan, Ngapudaw, Pathein, and Pyinzalu- feature no breeding sites and therefore have low ecological value. Thus, Hinthada Township is a priority place for fisheries resources protection and management measures.

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5 BIBLIOGRAPHY

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Baran E, Win Ko Ko, Zi Za Wah, Estepa N, Saray S, Tezzo X, Khin Myat Nwe and Maningo E. 2015. Distribution, migrations and breeding of Hilsa (Tenualosa ilisha) in the Ayeyarwady system in Myanmar. Yangon, Myanmar: Ecology-39- BOBLME, Bay of Bengal Large Marine Ecosystem project.

Chan Sokheng, Putrea Solida and Leang Sopha. 2008. Using local knowledge to inventory deep pools important fish habitats in Tonlé Sap and mainstream around Great Lake in Cambodia. In Burnhill TJ and Bamrunggrach P, eds. Proceedings of the 8th Technical Symposium on Mekong Fisheries, 15th– 17th November 2006. MRC Conference Series No. 7. Vientiane, Laos: Mekong River Commission. 43- 63.

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Johannes RE. 1981. Working with fishers to improve coastal tropical fisheries and resource management. Bulletin of Marine Science 31(3). 673–680.

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Moller H, Berkes F, Lyver PO and Kislalioglu M. 2004. Combining science and traditional ecological knowledge: monitoring populations for co-management. Ecology and Society 9(3); 2. http://www.ecologyandsociety.org/vol9/iss3/art2.

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Poulsen AF and Jorgensen JV. 1999. Survey manual for the use of local fishers' knowledge in the study of fish migrations and spawning in the Mekong River Basin. (Basin wide) Assessment of Mekong Fisheries – AMFP Technical Report 1/99 version 1.0. Vientiane, Lao PDR: Mekong River Commission.

Poulsen AF, Valbo-Jørgensen J, Chan Sokheng, Chhuon Kim Chhea, Sintavong Viravong, Kongpeng Bouakhamvongsa, Thavone Phommavong, Ubolratana Suntornratana, Noppanum Yoorong, Nguyen Thanh Tung et al. 2000. Fish migrations and spawning habits in the Mekong mainstream: A survey using local knowledge (Basinwide). AMFC Technical Report. Mekong River Commission. Vientiane, Lao PDR: Mekong River Commission.

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6 ANNEX 1: MONTHLY DISTRIBUTION OF YIELDS

Table 5. Monthly distribution of yield in kg per fisherman and per day in the Central Dry Zone (average of all townships)

Species in CDZ Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mastacembelus armatus Pangasianodon hypophthalmus Macrognathus 3 3 1.5 zebrinus Ilisha megaloptera Anguilla anguilla

Hilsa kelee

Bagarius yarrelli

Lates calcarifer

Gudusia variegata Silonia silondia 3 2 3 2 3 2 3 4 5 1.3 3 2 Sperata aor 5 12

Labeo calbasu 6 6 6 0.5

Catla catla

Bagarius 20 50 50 3 bagarius Cirrhinus cirrhosus/ 3 6 5 30 10 mrigala Wallago attu 9.3 22 4.8 3 3 3 6 10 30 27

Hemibagrus 5 3 microphthalmus Pangasius 9 11 14 27.5 25 16 23 10 25 10 pangasius Rita rita 11 18 25 6 30 60 60 18 20

Tenualosa ilisha 15 1.6 1.4 1 1 1.7 5.3

Pangasius 4 36 9.8 conchophilus

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Table 6. Monthly distribution of yield in kg per fisherman and per day in the Ayeyarwady Delta (average of all townships)

Species in Delta Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mastacembelus 1 armatus Pangasianodon 2 hypophthalmus Macrognathus 3 zebrinus Ilisha 2 1 0.5 19 megaloptera Anguilla anguilla 15 15

Hilsa kelee 4 2 2 2 2.5 3 3 3.5 3.5 5

Bagarius yarrelli 3 3 2 6.7 5 12

Lates calcarifer 5 3 6.7 5.5 15 10

Gudusia 30 20 variegata Silonia silondia 3.5 6 3.8 15 15 2.5 2.5 1 5 4.3 6.7 2 Sperata aor 15 15 15 10 5 5 3 3 6 5.5 5 1 Labeo calbasu 1.5 1 1 0.8 1 2.8 5 3 45 20 4.5 5 Catla catla 6.5 8 9.3 8.5 20 10 10 13 19 12 6.2 9.5 Bagarius 3 3 2 5.5 3.5 6.5 bagarius Cirrhinus cirrhosus 4.8 7.8 7.9 6.4 7.3 30 5 45 14 7.9 12 8.4 /mrigala Wallago attu 4.8 7 16 11 6 9 6 16 17 16 19 5.8 Hemibagrus 45 75 75 0.8 1.9 0.8 14 6 75 75 microphthalmus Pangasius 18 17 12 18 35 15 7.5 18 28 33 23 pangasius Rita rita 5 12 42 53 57.7 5 35 35 8.9 50 70 33 Tenualosa ilisha 74 70 67 83 103 35 2.8 75 47 56 58 39 Pangasius 20 15 33 64 108 240 105 73 54 81 66 48 conchophilus

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7 ANNEX 2: DETAILS BY MIGRATORY SPECIES SURVEYED

7.1 Migratory species with no known breeding sites Only two species are considered migratory, but without known breeding sites. These species are Hilsa kelee and Ilisha megaloptera.

Hilsa kelee Hilsa kelee is usually found in marine, fresh and brackish waters. This species is pelagic- neritic and anadromous. This species can reach a maximum size of 35 cm, but the common length observed at first maturity is 16.5 cm. It is widely distributed in Indo-West Pacific; probably all coasts of Indian Ocean, from Gulf of Oman and Gulf of Aden south to Transkei, South Africa and Madagascar, across the Bay of Bengal, Gulf of Thailand, Java Sea and north to Hong Kong and east to Papua New Guinea and possibly further. It is found in coastal waters, enters estuaries and is able to tolerate quite low salinities (7 ppt). Hilsa kelee primarily feeds on phytoplankton (mainly diatoms, also dinoflagellates), but also copepods, molluscan and crustacean larvae, prawns, amphipods and polychaetes. It spawns (at least in Godavari estuary) around February.

In the Central Dry Zone, Hilsa kelee is reported in Kyangin only during October and November. Catch during both months is a low value of approximately 5 kg per day. It is considered to be a young adult when it reaches 15 inches (38 cm). The migratory status of this species is unclear.

In the delta, Hilsa kelee is reported in Wakema year-round, with the exception of July and August. Size varies monthly, but juveniles (10 inches or 25 cm) are found in December, January and April, while young adults (15 inches or 38 cm) are caught during the other months. The highest yield is reported in November and December, at around 8 kg per day. Fishermen report that this species migrates upstream during its occurrence.

Hilsa kelee is caught by drift nets in Ayeyarwady River.

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Figure 9: Distribution of Hilsa kelee in the Central Dry Zone

Figure 10: Distribution of Hilsa kelee in the Ayeyarwady Delta

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Ilisha megaloptera Ilisha megaloptera thrives in marine, fresh and brackish waters. It is a pelagic-neritic and anadromous species. The maximum length is 28 cm. This species is usually found in the Indo-Pacific: Indian Ocean (Bombay to Bay of Bengal and Andaman coast of Thailand), Java Sea (off Java, Singapore). I. megaloptera is considered as an inshore species, but apparently occurs also in rivers (Ganges at Allahabad and rivers of eastern Uttar Pradesh, but not in Velar estuary). It ascends into the upper end of the tidal zone. It feeds on fishes, crustaceans, amphipods, occasionally polychaetes, tunicates and small amounts of algae and diatoms.

Ilisha megaloptera is only caught in Mawgyun of the eastern part of the delta between April and June. It reaches a size of 10 inches (25cm), which can be regarded as juveniles. Yield is highest at around 3 kg per day in April, and this species is observed to move upstream.

In the Coastal Central Zone, Ilisha megaloptera is reported to be harvested only in Bogale. This species occurs only in August; then the size is 10 inches (25 cm), which can be considered as juveniles. Yields of around 30 kg per day during its occurrence period are reported, and fishermen are unaware of the migratory status of this species.

Illisha megaloptera is caught by drift nets in floodplains of Bogale and Yarzudaing River.

Figure 11: Distribution of Ilisha megaloptera in the Ayeyarwady Delta

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7.2 Non-migratory species with breeding sites

Six species are not considered migratory, but featured breeding sites in the study areas. These species include Bagarius bagarius, Cirrhinus mrigala, Gudusia variegata, Hemibagrus microphthalmus, Pangasianodon gigas, and Sperata aor.

Bagarius bagarius Bagarius bagarius breeds along the Ayeyarwady River in Pyay, at a site that is over 10 km long. This site is home to only this species. Sandy beaches and islands are spotted at the spawning area indicating that the water is shallow over there.

Bagarius bagarius is caught by drift nets and set gill nets in the Ayeyarwady River, and by drift nets in the Nga Wann River.

Figure 12: Breeding sites of Bagarius bagarius

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Cirrhinus mrigala The breeding sites are located in Hinthada, Ingapu, Kalewa, Katha, and Monyo. Cirrhinus mrigala breeds along floodplains of the Chindwin River, shallow waters at the upper limit of the Ayeyarwady River, shallow waters and floodplains at the lower part of the Ayeyarwady River, and floodplains of the Pathein River.

Ingapu features the biggest breeding site for this species. This 17 km long site is surrounded by sand beaches. Cirrhinus mrigala is found breeding from July to August, as determined from the presence of larvae and juveniles that are 0.5 inches long at that time.

In Katha, the fish spawn in March-April, and the species is present again in August at a size of 2.5-3 inches. In Kalewa, the juvenile fish size is 1 inch in August. The species also breeds in July-August in Monyo (the size of individuals found at that time reaches 1.5 to 2 inches). In Hinthada, the species breeds in June-July, as identified by individuals that reach 1 inch in size.

Figure 13: Breeding sites of Cirrhinus mgrigala

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Gudusia variegata In Hinthada Township, Gudusia variegata’s breeding site is over 38 km long, and is the only breeding site identified in the Delta for this species. The species breeds along the right bank of the Ayeyarwady River in sand beaches and floodplains. The fish is found breeding in March-April, with 0.5 inches larvae and juveniles found then.

Gudusia variegata is caught by set gill nets in the Ayeyarwady and Nga Wann River.

Figure 14: Breeding sites of Gudusia variegata

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Hemibagrus microphthalmus Hemibagrus microphthalmus’ breeding sites are located in three townships along the Ayeyarwady River channel: Ingapu, Myanaung, and Myinmu.

The biggest breeding site is in Ingapu, where Hemibagrus microphthalmus breeds from July to August, as identified by larvae and juveniles then reaching 1.5-2 inches.

In Myinmu, the fish breeds on the sandy areas of the Ayeyarwady River. Hemibagrus microphthalmus’ spawning season is from June to July. In August, the fish size at that timeranges from 0.5 to 1 inches. In Myanaung, the fish is found in July, when it reaches a size of 0.5 inches. Along the Ayeyarwady River, the breeding site is on the right bank of the sandy island, and is over 6 km long.

Hemibagrus microphthalmus is caught by beach seine nets, drift nets and set gill nets in Ayeyarwady River, and by drift nets in Nga Wann River.

Figure 15: Breeding sites of Hemibagrus microphthalmus

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Pangasianodon gigas Pangasianodon gigas breeds at the junction of Toe River and Twantay Canal, in the Twantay Township. This is the only breeding site identified in the Delta for this species.

Figure 16: Breeding sites of Pangasianodon gigas

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Sperata aor Sperata aor breeds in three different locations: Mandalay, Hinthada, and Zalun. Hinthada features the biggest breeding site that is over 9 km long. The breeding area is on the left river bank of the floodplains, and is full of shallow sand beaches.

The breeding site in Mandalay is over 6 km long. The area is full of sand beaches and very shallow. This species is found in April-May, reaching a size of 3-4 inches at that time. Since this size is already big, it is unsure whether Mandalay is the breeding area. In Zalun, Sperata aor breeds along the Ayeyarwady River at a site that is over 6 km long. The fish is found breeding on the left bank in the floodplains; the site is sandy as well.

Sperata aor is caught by drift nets and set gill nets in the Ayeyarwady and Nga Wann River, and by set gill nets in Toe River.

Figure 17: Breeding sites of Sperata aor

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7.3 Migratory species with breeding sites

Ten species, including Tenualosa ilisha which was extensively discussed in a separate report, were identified to breed in the survey places, and considered migratory as well. These species include: Catla catla, Cirrhinus cirrhosus, Labeo calbasu, Lates calcarifer, Pangasius conchophilus, Pangasius pangasius, Rita rita, Silonia silondia, Tenualosa ilisha, and Wallago attu.

Catla catla Catla catla is found in fresh and brackish waters, and is considered a benthopelagic and potamodromous species. The maximum length recorded is 182 cm with a weight of 38.6 kg. This species usually thrives in Asia, particularly in Pakistan, India, Bangladesh, Nepal and Myanmar. The adults occur in rivers, lakes and culture ponds, and mature individuals breed in rivers. Catla catla is a surface and mid-water feeder; this species is mainly omnivorous, with juveniles feeding on aquatic and terrestrial insects, detritus and phytoplankton.

In the Central Dry Zone, Catla catla is only harvested in Monyo. It is caught between February and April, and between September and December. Adult fish longer than 20 inches (52 cm) are caught during the first season, and during November and December of the second season. Fishermen can catch high yields at around 50 kg per day during September and October; these are also the months when smaller individuals (15 inches or 38 cm) are caught. When they find the species in their catch, fishers are not sure whether that species is migrating or not.

In the eastern part of the delta, Catla catla is harvested in seven townships (Kyangin, Myanaung, Zalun, Danubyu, Yandoon, Maubin and Twantay), and is found at different times in each township. For example, in Kyangin, fishermen catch Catla catla between September and November, but in Myanaung, fishermen catch this fish between February and April, and October and December. In coastal townships this species is present during fewer months. In Twantay, yield is highest at around 135 kg per day in September, but size is smaller at around 10 inches (25 cm). Danubyu has the lowest daily yield, with less than 10 kg. When they find the species in their catch, fishers are not sure whether that species is migrating or not.

In the western part of the delta, Catla catla is harvested in five townships, (Ingapu, Yegyi, Thabaung, Pathein and Mawgyun) and is caught between September and November. Species size is smaller (10 – 15 inches or 25 – 38 cm) compared with the other zones. Yield is highest in Ingapu at around 35 kg per day in September. The lowest catch in this zone is in Mawgyun Township at less than 5kg per day in November. Fishermen observed this species to migrate in Ingapu and Mawgyun Townships.

Catla catla species is harvested in the Pyapon and Bogale Townships of the coastal central zone of the Ayeyarwady River. This species is harvested during September and October. The biggest size caught is over 20 inches or 52 cm (assumed to be adults) in Bogale Township. Juveniles, considered at a size of 10 inches (25cm), are caught during September and October in Pyapon. Yield in Pyapon Township is less than 5 kg per day compared with the

36 | yield in Bogale at around 50kg per day. Fishermen observe migration of this species in Pyapon Township during the months of its occurrence.

Table 7. Fishing gears used to catch Catla catla

Habitat Type Habitat Name Gears Used Flood plain Bogale River Drift nets Drift nets Paddy field Pyapon Township

Drift nets Ayeyarwady River Set gill nets Chindwin River Cast nets River Nga Wann River Drift nets Cast net Toe River Drift nets Yarzudaing River Drift nets River bank Pyapon River Drift nets

Figure 18: Migration of Catla catla in the Central Dry Zone

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Figure 19: Distribution of Catla catla in the Central Dry Zone

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Figure 20: Distribution of Catla catla in the Ayeyarwady Delta

Figure 21: Migration of Catla catla in the Ayeyarwady Delta

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Breeding sites of Catla catla Catla catla breeds along 4 different rivers including the Chindwin River, Ayeyarwady River, Pathein River, and Toe River. The breeding sites are located in 12 cities: Kalewa, Kyangin, Myanaung, Monyo, Ingapu, Hinthada, Zalun, Danubyu, Yandoon, Twantay, Ngathaingchaung, and Wakema.

The biggest breeding site is in the floodplains along the Pathein River, right after splitting from the Ayeyarwady River. This site stretches for 17 km, and is surrounded by sand beaches.

Catla catla breeds from July to August, as attested by fishes of 1 inch in Ingapu, and 1 to 1.5 inches in Monyo. Catla catla breeds from May to June in Danubyu and Yandoon. It also breeds along both sides of floodplains in Wakema.

There is no information about breeding times in the other townships mentioned above.

Figure 22: Breeding sites of Catla catla

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Cirrhinus cirrhosus Distribution of Cirrhinus cirrhosus Cirrhinus cirrhosus is found in fresh and brackish water environments and is benthopelagic and potamodromous. It can grow as big as 100 cm, although the common observed length is 40 cm. This species is distributed in Asia, and is native to large rivers in the Indian subcontinent. Adults inhabit fast flowing streams and rivers and can tolerate high levels of salinity. Juveniles (TL<5 cm) are omnivorous, and adults are almost entirely herbivorous; they feed on plankton, but also graze on algae. Spawning occurs in marginal areas of the water bodies with a depth of 50-100 cm over a sand or clay substrate. A 6 kg female can lay one million eggs (1 mm in diameter). This is a very active fish that thrives in ponds and spawns in swift rivers. This fish is widely cultured in India but fails to breed naturally in ponds, thus induced breeding is done. Fish are harvested at about 3 years, with a length of 40 cm and a weight of 1000 g. Between July and November, fingerlings are in great demand for stocking ponds.

Cirrhinus cirrhosus is caught in Myinmu and Monyo of the Central Dry Zone. Juveniles are observed between November and January of the following year, the size of the fishes ranging between 5 and 10 inches (13cm -25cm). During February and March, fish sizes are larger, reaching 20 inches (52 cm). This can be regarded as the main season of migration with the highest yield of around 50 kg per day, starting in November. In Monyo, Cirrhinus cirrhosis individuals are observed over more months, and harvesting takes place from September until March of the following year. Yield is highest during September and October, at around 25 kg per day. Fish reach their adult size of 20 inches (52 cm) during December. When they find the species in their catch, fishers are not sure whether that species is migrating or not.

Cirrhinus cirrhosus is caught in six townships (Ingapu, Yegyi, Wakema Thabaung Pathein and Mawgyun) of the western part of the delta between September and December. Juveniles and young adults are caught in this zone, ranging between 10 and 15 inches (25 – 36 cm). Highest yield is reported in Wakema and Ingapu Townships at around 35 kg per day during September and November. Fishermen observed migration only in Ingapu Township during its occurrence.

Cirrhinus cirrhosus adults and young adults are caught in the upper townships (Kyangin and Danubyu) of the eastern part of the delta. This species occurs during different months in each township. This species is not harvested between June and August (this is the closed season) but is harvested in two seasons in five townships (Myanaung, Zalun, Danubyu, Yandoon and Maubin). Small sized fish (5 – 10 inches (13 – 25 cm)) are caught within the coastal zone, Twantay, Maubin and Dedaye Townships. Yield is highest in Myanaung Township at around 35 kg per day during February and March, followed by Yandoon Township at around 25 kg per day between February and April. Lowest yield is reported in Maubin and Dedaye Townships at 5 kg per day. When they find the species in their catch, fishers are not sure whether that species is migrating or not.

Cirrhinus cirrhosus is caught in the Bogale and Pyapon Townships. In Bogale, this species is caught as a young adult only during September, when it reaches a size of 15 inches (or 38 cm). Yield is higher at around 20 kg in Bogale, compared to less than 5 kg in Pyapon.

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However, fish size (20 inches or 52 cm) is bigger in Pyapon. In Pyapon, fishermen observed this species migrating downstream.

Table 8. Fishing gears used to catch Cirrhinus cirrhosus/mgrigala

Habitat Type Habitat Name Gears Used Flood plains Bogale River Drift nets Paddy field Pyapon Township Drift nets Beach seine nets Ayeyawaddy River Drift nets Set gill nets Long lines Chindwin River River Cast nets Nga Wann River Drift nets Cast nets Toe River Drift nets Yarzudaing River Drift nets River bank Pyapon River Drift nets Other Surrounding nets

Figure 23: Migration of Cirrhinus cirrhosus in the Central Dry Zone

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Figure 24: Distribution of Cirrhinus cirrhosus in the Central Dry Zone

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Figure 25: Migration of Cirrhinus cirrhosus in the Ayeyarwady Delta

Figure 26: Distribution of Cirrhinus cirrhosus in the Ayeyarwady Delta

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Breeding sites of Cirrhinus cirrhosus Cirrhinus cirrhosus’ breeding behavior is very similar to that of Catla catla. It breeds along 3 rivers; Ayeyarwady River, Pathein River, and Toe River. The sites are located in Ingapu, Myanaung, Danubyu, Zalun, Yandoon, Twantay, and Yegyi (Ngathaingchaung) Township.

The biggest breeding site is in the floodplains along the Pathein River in Ingapu, where the fish breeds in the floodplains along the Pathein River. This breeding site is 17 km long and is surrounded by sand beaches. In Ingapu, Cirrhinus cirrhosus is found breeding from July to August, as determined by the presence of larvae/juveniles that are 0.5 inches long at this time.

According to the fishermen interviewed, Cirrhinus cirrhosus is also found breeding from May to June in Danubyu and Yandoon.

There is no information about breeding times in the other townships mentioned above.

Figure 27: Breeding sites of Cirrhinus cirrhosus

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Labeo calbasu Distribution of Labeo calbasu Labeo calbasu thrives in fresh and brackish water; it is demersal and potamodromous. The maximum recorded length of this species is 90 cm and its length at maturity is 32.8 cm. This species is distributed in Asia, including Pakistan, India, Bangladesh, Myanmar, Nepal, Thailand and South Western China. The adult fish occur in slow-moving waters of rivers and ponds. They feed on plants, filamentous algae and diatoms. Fecundity of 2 specimens (38.8- 40.5 cm) ranged between 193,000 and 238,000 eggs.

Labeo calbasu is only harvested in the Myinmu Township of the Central Dry Zone. Juveniles are caught between August and November, at a size of about 5 inches (13 cm). Yield is around 10 kg per day during the first three months, followed by an abrupt drop of less than 1 kg per day in November. When they find the species in their catch, fishers are not sure whether that species is migrating or not.

Labeo calbasu species is caught in Ingapu and Thabaung in the western part of the delta . It is harvested in Ingapu between September and August, with a catch size of 5 inches or 13 cm (assumed to be young juveniles), during the first two months of its occurrence. September yields are highest at around 25 kg per day. Although the fish caught are bigger in August (10 inches or 25cm), yield is lower at about 5 kg per day (this can be assumed to be the last batch of juveniles migrating to this township). In Thabaung, this species only occurs in May as juveniles, where it reaches a size of 10 inches or 25 cm and a very low yield of 1 kg per day. This species is observed to be migrating only in the Ingapu Township of this zone.

In the eastern part of the delta, fishermen catch Labeo calbasu in four townships (Kyangin, Myanaung, Ngayaungdon and Maubin). This species occurs over four months in Kyangin, while it is only found one month a year in the other townships. In Kyangin, the first harvest season is between April and June, and the second harvest is in October. The fish size caught in this zone is smaller, at 5 – 10 inches (13 – 25 cm; assumed to be juveniles). Low yields of less than 1 kg per day are observed in all townships except in the Myanaung, where fishermen can catch up to 15 kg per day. When they find the species in their catch, fishers are not sure whether that species is migrating or not.

Labeo calbasu is caught by drift nets and set gill nets in Ayeyarwady River, by cast nets in Chindwin River, and by drift nets in Nga Wann and Toe River.

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Figure 28: Distribution and migration of Labeo calbasu in the Central Dry Zone

Figure 29: Distribution and migration of Labeo calbasu in the Ayeyarwady Delta

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Breeding sites of Labeo calbasu Labeo calbasu breeds in 4 different rivers (Ayeyarwady River, Chindwin River, Pathein River, Toe River) in 8 townships (Katha, Kalewa, Pakokku, Ingapu, Myanaung, Hinthada, Maubin, and Yandoon).

Ingapu has the biggest breeding site, with 17 km long floodplains along Pathein River right after splitting from Ayeyarwady River. The site consists of sand beaches. Labeo calbasu is found breeding from July to August, as determined from the presence of larvae and juveniles that are 0.5 inches long at that time.

In Hinthada, the species spawn in June-July, as attested by the presence on 1 inch long juveniles. Labeo calbasu inhabits creeks from March to August and comes back to the river from September to February.

Figure 30: Breeding sites of Labeo calbasu

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Lates calcarifer Distribution of Lates calcarifer Lates calcarifer, also named barramundi, thrives in marine, fresh and brackish waters. It is demersal and catadromous species. It has a maximum length of 200 cm, a common length of 150 cm and a published weight of 60 kg. This species usually inhabits the Indo-West Pacific: the eastern edge of the Persian Gulf to China, Taiwan and southern Japan, southward to southern Papua New Guinea and northern Australia. It is found in clear to turbid waters of coastal waters, estuaries and lagoons. It is a diadromous fish, inhabiting rivers before returning to the estuaries to spawn. It is also a protandrous hermaphrodite (individuals are males for one or more spawning seasons before undergoing sex inversion). The larvae and young juveniles live in brackish temporary swamps associated with estuaries, and older juveniles inhabit the upper reaches of rivers. Maturing male barramundi migrate downstream from freshwater habitats at the start of the wet (monsoon) season. They spawn with resident females in estuaries and on tidal flats outside the mouths of rivers. Barramundi spawn on the full moon and new moon, primarily at the beginning of an incoming tide which carries the eggs into the estuary. Barramundi are broadcast spawners that aggregate to spawn around the mouths of rivers. While adults and juveniles are capable of living in fresh water, brackish waters are required for embryonic development. This species prefers cover on undercut banks, submerged logs and overhanging vegetation. It feeds on fishes and crustaceans. Juveniles also eat insects. Lates calcarifer is used for aquaculture in Thailand, Indonesia and Australia.

Lates calcarifer is harvested in three townships of the western part of the delta (Wakema, Mawgyun and Labutta). Harvesting begins between October and January particularly in Wakema. The size caught in the western part of the delta ranges from 5 to 10 inches (13 – 25 cm); it can be regarded as juveniles. In Mawgyun, smaller fish are harvested (5 inches or 13 cm; juveniles). In Wakema, yield is high during November at 115 kg per day, followed by an abrupt drop to around 20 kg per day in December. Yield in the two townships is lower at less than 10 kg per day. Fishermen in Mawgyun observed that this species is migrating during the time of its occurrence.

In the eastern part of the delta, Lates calcarifer is harvested in only the Dedaye Township between August and October. Size of individuals increases over months; a smaller size (5 inches or 13 cm) is caught in August, while a bigger size is caught in September (10 inches or 25 cm) and October (15 inches or 38 cm). Yield is highest during September at around 8kg per day. When they find the species in their catch, fishers are not sure whether that species is migrating or not.

Lates calcarifer is harvested in three townships (Pyapon, Bogale and Labutta) of the coastal zone between September and November. In the Labutta Township, it is only harvested during October and November. Groups of juveniles and young adults (10 – 15 inches or 25 – 38 cm) are caught in Pyapon, and young adults (15 inches (38 cm) in the other townships. Yield is highest in Bogale at around 35 kg per day and lowest in Pyapon at around 1 kg per day. Fishermen observed migration only in Pyapon during the months of its occurrence.

Lates calcarifer is caught by drift nets almost everywhere.

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Figure 31: Migration of Lates calcarifer in the Ayeyarwady Delta

Figure 32: Distribution of Lates calcarifer in the Ayeyarwady Delta

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Breeding sites of Lates calcarifer Lates calcarifer’s breeding sites are located in seven townships: Bogale, Dedaye, Kyaik Hto, Mawgyun, Pyapon, Thanatpin, and Waw.

In Dedaye, the breeding site is on floodplains at the right bank of Toe River, and extends towards the shallow area of Donyan River and floodplains all around. Lates calcarifer’s breeding site stretches over a length of 30 km and a width of 23 km. Remarkably, Dedaye Township is home to only Lates calcarifer. In Pyapon the breeding site for Lates calcarifer is over 25 km long, and the species breeds along the mainstream of Pyapon River. As shown in the map below, Pyapon River flows directly down to the sea. The breeding site in Mawgyun is the combination of the Myngagon River and the lower part of the Ayeyarwady River. Stretching over 25 km, the area consists of sand beaches and floodplains. In Bogale, the breeding site covers an area of 34 km and contains two rivers: Bogale River and Kyondon River. The area is very sandy, and few parts are floodplains. Breeding takes place within Kha lem creeks in Kyaik Hto. The spawning season is between May and June. At the lower part of the Salween River, 1 inch larvae are found in March in Kyaik Hto and Thanatpin. Breeding takes place within small concrete creeks in paddy fields in Waw. The spawning season is between May and June. In July, 1-1.5 inch fish are found in paddy fields.

Figure 33: Breeding sites of Lates calcarifer

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Pangasius conchophilus Distribution of Pangasius conchophilus Pangasius conchophilus thrives in fresh water and is benthopelagic and potamodromous. The maximum length recorded is 120 cm. This species is found in Asia, in particular the Mekong, Bangpakong, and Chao Phraya basins. It occurs in large rivers and enters flooded forests. It is found in rapids and in deep slow reaches. Juveniles feed on prawns and insects, and sub-adults and adults feed on prawns, insects and particularly mollusks. It migrates into the middle Mekong along the Thai-Lao border as water levels and turbidity begin to increase. This species reproduces early in the flood season, and 6 to 7 cm juveniles are caught by late June. This species is usually marketed as fresh.

Pangasius conchophilus is harvested in three townships (Pakokku, Magway and Monyo) of the Central Dry Zone. This species occurs in two seasons; the first season is between September and December, and the second season is between February and April. The catch size is 20 inches or 52 cm, which can be regarded as adults. Yield is highest in Magway in March and Monyo in October, at around 100 kg per day. The lowest yield is around 2 kg per day, which is recorded in Pakokku Township during April. It can be assumed that migration starts from Monyo during the last quarter of the year, and then passes through Magway and Pakokku during the first quarter of the following year. Yield can also indicate migration, showing low catch in the northern part of this zone. However, only the fishermen from Monyo mentioned that they are aware of migration of this species during the time of harvest.

Pangasius conchophilus is harvested in four townships (Yegyi, Thabaung, Ngapudaw and Labutta) of the western part of the delta between April and December. It occurs most frequently in the southern townships of this zone, and less frequently as it moves towards the northern part townships. The fish caught are 20 inches or 52cm in all townships (assumed to be adults). The highest yield is in Thabaung Township of around 60 kg per day, and the lowest yield is in Ngapudaw at 5 kg per day. Migration can be traced based on yield in each township: e.g. in Labutta, yield is lower towards the end of the months of occurrence, while yield increases in the next townships (Ngapudaw) on its first following month.

Pangasius conchophilus is harvested in seven townships of the eastern part of the delta. In the southeast, this species is caught between September and December, while in the central and northern part of the delta, it is caught between January and May during the first harvest season, and between September and December during the second harvest season. Fishermen in six of the seven townships report a common catch size of 20 inches or 52 cm, excluding Maubin, where fishermen report a catch size of 15 inches or 38 cm in both months. Yield is highest in Kyangin and Twantay during October at 200 kg per day. Lowest yield is reported in Maubin Township at around 10 kg per day during its three months of occurrence. Most of the fishermen are not aware of the migration patterns of this species in their own townships. Only fishermen from Twantay, Maubin and Dedaye Townships mentioned that they observed migration.

In the central part of the coastal zone, Pangasius conchophilus is harvested in Labutta Township. This species occurs only during July in this township. Size caught during this

52 | occurrence is 20 inches or 52cm. The reported yield per day is around 80 kg. Fishermen observed this species to migrate downstream during the time of its occurrence.

Pangasius conchophilus is caught by drift nets in flood plains and paddy field of Toe River, by drift nets in Ayeyarwady, Nga Wann, Toe, Yangon, and Ywe River.

Figure 34: Migration of Pangasius conchophilus in the Central Dry Zone

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Figure 35: Distribution of Pangasius conchophilus in the Central Dry Zone

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Figure 36: Migration of Pangasius conchophilus in the Ayeyarwady Delta

Figure 37: Distribution of Pangasius conchophilus in the Ayeyarwady Delta

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Breeding sites of Pangasius conchophilus

Pangasius conchophilus’ breeding sites are located in 4 areas: Kyangin, Yandoon, Twantay, and Kyauktan Township.

The biggest breeding site is in Twantay Township, which stretches over 17 km on the mainstream of Toe River, and extends another 2 km toward Twantay Canal. There are no remarkable features spotted at the breeding site.

Pangasius conchophilus breeds over 6 km in Yandoon along the Ayeyarwady River. Two of the 1 km-long Ayeyarwady Bridges are located in this area. The fish is found from May to June along the concrete of bridges; its size reaching 2-4 inches. The species is found breeding in July-August in Kyangin, reaching a size of 1-1.5 inches in May.

Figure 38: Breeding sites of Pangasius conchophilus

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Pangasius pangasius Distribution of Pangasius pangasius Pangasius pangasius thrives in fresh and brackish water and is benthopelagic and potadromous. The maximum length recorded is 300 cm. This species is usually found in Asia in large rivers of the Indian subcontinent and Myanmar (Ganges, Krishna, Godavari, Irrawaddy). It is widely introduced in its geographical range for aquaculture. This species occurs in high estuary (freshwater tidal zone) as juveniles, moving to brackish waters as sub- adults, and finally to river mouths and inshore areas as adults. It feeds on snails, other mollusks and plants.

Pangasius pangasius is caught in five townships (Katha, Kalewa, Pakokku, Myingyan and Pyay) of the Central Dry Zone. This species is found over more months in the northern part of the CDZ. According to fishermen, this species is caught between February and November, with the exception of June. The central and southern parts of CDZ have fewer months of occurrence, particularly in Mawgyun where this species is only caught in December. Yield is also high in the northern townships at around 80 kg per day, and yield is lowest in Myingyan at only 3 kg per day. Fishermen observed this species to migrate only in Kalewa Township.

Pangasius pangasius is harvested in the Ingapu, Wakema and Mawgyun Townships of the western part of the delta. This species is found over five months in Wakema, two months in Ingapu and once a year in Mawgyun. The size of fish caught is similar in all townships at 20 inches or 52cm (assumed to be young adults). Yield is highest in Wakema at around 80 kg per day during November and December. Yield is also lowest at 5 kg per day in this township during February. Fishermen observed migration of this species in Ingapu and Mawgyun Townships.

Pangasius pangasius is harvested in seven townships of the eastern part of the delta. It is caught during the third and last quarters of the year in the southern part of this zone. At the central and northern part, this species is usually caught in two seasons between January and April, and October and December. In almost all townships, the size caught is 20 inches or 52 cm except in Maubin Township where the size caught is 15 inches or 38 cm. The highest yield is reported in Twantay Township at around 120 kg per day during November, and the lowest yield is 8 kg per day in Myanaung Township during January. Migration is reported in Yandoon, Myanaung, Maubin, Dedaye and Twantay.

Pangasius pangasius is harvested in the Pyapon and Bogale Township of the Coastal Central Dry Zone. In Pyapon, this species is caught during September and October, and in Ingapu during January and February. The size caught in both townships is 20 inches or 52 cm. The highest yield reported in this zone is around 60 kg per day at Bogale Township during January. Fishermen in both townships observed the migration of this species in their fishing area.

Pangasius pangasius is caught by drift nets everywhere.

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Figure 39: Migration of Pangasius pangasius in the Central Dry Zone

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Figure 40: Distribution of Pangasius pangasius in the Central Dry Zone

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Figure 41: Migration of Pangasius pangasius in the Ayeyarwady Delta

Figure 42: Distribution of Pangasius pangasius in the Ayeyarwady Delta

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Breeding sites of pangasius pangasius Pangasius pangasius’ breeding sites are located in 5 townships: Hinthada, Htantabin, Myanaung, Kyaik Hto, Twantay, and Pyapon.

The biggest breeding site is over 20 km long, and is along the mainstream of the Pyapon River in Pyapon. Pangasius pangasius is found in Myanaung from December to April, reaching a size of 7 inches. Along the Ayeyarwady River, the breeding site is over 6 km long and is on the right bank of the sandy island. In Htantabin, Pangasius pangasius breeds along the sandy part of the Yangon River. This shallow area is 5 km long from May to June. Fish size in this zone reaches 2.5-3.5 inches at that time. In Kyaik Hto, the breeding season is between September and October, and the larvae reach a size of 2 inches. The area consists of sandy beaches with shallow waters along the Salween River.

Figure 43: Breeding sites of Pangasius pangasius

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Rita rita Distribution of Rita rita Rita rita species thrives in fresh and brackish water. It is demersal and potamodromous. The maximum length recorded is 150 cm. It is found in Asia: Afghanistan, Pakistan, India, Nepal, Bangladesh and Myanmar. This species inhabits rivers and estuaries, preferably muddy to clear water. It prefers the backwater of quiet eddies and feeds on insects, mollusks, shrimps and fishes.

Rita rita is harvested in five townships of the Central Dry Zone, including Kalewa, Pakokku, Katha, Pyay and Magway. Occurrence of this species in the northern and southern part of this zone differs. This species is found only in January in Katha and Kalewa Townships while in the other three townships there are two harvest seasons. The size harvested differs from each township. However, juveniles and young juveniles that are 5-15 inches long (13 – 38 cm) are caught in the southern part of this zone, while adults of 20 inches (52 cm) are caught in the central part of this zone. It is also in this zone that the highest yield of around 60 kg per day is reported. The lowest yield is reported in Katha and Kalewa at around 2 kg per day during the month of its occurrence. Fishermen are not aware if this species is migrating in their fishing area.

In the western part of the delta, Rita rita is harvested in Thabaung, Wakema and Mawgyun Townships. This species occurs in Mawgyun during September and October, in Ingapu between February and April and in Thabaung in June. Juveniles and young adults are caught in this zone, with the size ranging from 5 – 10 inches or 13 – 25cm. The highest yield is reported in Wakema at 50 kg per day during March. The smallest size (5 inches or 13 cm) and lowest yield (less than 1 kg/day) are reported in Mawgyun during the months of its occurrence. When they find the species in their catch, fishers are not sure whether that species is migrating or not.

Rita rita species is harvested in six townships (Kyangin, Myanaung, Danubyu, Zalun, Maubin and Yandoon) of the eastern part of the delta. The species is harvested over two seasons in four townships (Kyangin, Myanaung, Danubyu and Yandoon Townships). Juveniles and young adults are usually caught in the five townships, except in Danubyu, where adults are caught. Yield is highest in Kyangin, of more than 300 kg per day, while catch is lowest in Maubin Township at around 10 kg per day. Migration is observed in four out of the six townships; these include Zalun, Maubin, Yandoon and Danubyu.

Rita rita is caught by drift nets and set gill nets in Ayeyarwady and Nga Wann River, by long lines in Toe River, by drift nets in Yarzudaing River, and by surrounding nets in other places.

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Figure 44: Migration of Rita rita in the Central Dry Zone

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Figure 45: Distribution of Rita rita in the Central Dry Zone

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Figure 46: Migration of Rita rita in the Ayeyarwady Delta

Figure 47: Distribution of Rita rita in the Ayeyarwady Delta

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Breeding sites of Rita rita Rita rita’s breeding sites are located in 4 areas: Pyay, Myanaung, Zalun, and Thabaung Township.

The biggest breeding site for Rita rita is over 10 km, and is along the Ayeyarwady River in Pyay. Sandy beaches and islands are spotted at the breeding sites, indicating shallow water. The species is found breeding in March and April, as determined from the presence of larvae and juveniles that are 1 inch long during that time.

In Pyay, Rita rita is found breeding over a 7 km area, and also found along the Ayeyarwady River over a 10 km long stretch. In Thabaung, Rita rita’s spawning months are during September and October along the Pathein River.

Figure 48: Breeding sites of Rita rita

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Silonia silondia Distribution of Silonia silondia Silonia silondia thrives in fresh and brackish water. It is demersal and amphidromous. The maximum length is 183 cm and the common length is 100 cm. It is an Asian species that can be found in Pakistan, India, Bangladesh, Nepal and Myanmar. This species inhabit rivers and is usually found in shoals. The adults ascend from estuaries into large rivers for breeding during monsoons. After the water level recedes, they often get stranded in small pools. It is an oviparous species and eggs are unguarded.

Silonia silondia is only harvested in the Patheingyi Township of the Central Dry Zone. During September and October, it is found in this township at a size of 10 inches or 25 cm (assumed to be young adults). The highest yield is about 10 kg per day during September. Fishermen observed that this species is migrating upstream when it is found.

In the western part of the delta, Silonia silondia is only harvested in Ingapu Township during September and October. Young adults are then caught (they reach a size of 10 – 15 inches; 25 – 38 cm). Yield is highest during September at around 15 kg per day. Migration of this species is observed during its occurrence.

In the eastern part of the delta, Silonia silondia is harvested in Yandoon and Twantay Townships. This species occurs in two seasons in Yandoon, the first harvest season is between January and March and the second season is between September and December. In Twantay, this species is found between September and November. Yield is highest during November at more than 10 kg per day. Fishermen are not aware about the migration pattern of this species in their fishing area.

Silonia silondia is caught by drift nets in Ayeyarwady, Nga Wann and Toe River.

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Figure 49: Distribution and Migraton of Silonia silondia in the Central Dry Zone

Figure 50: Distribution and migration of Silonia silondia in the Ayeyarwady Delta

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Breeding sites of Silonia silondia Silonia silondia breeds in 3 areas: Hinthada, Yandoon, and Maubin Township.

In Hinthada, the biggest breeding site is over 9 km long along the Ayeyarwady River and consists mainly of sand beaches and floodplains. The fish is found breeding on the left bank of the river in June (the size of individuals then reach 1 inch).

In Yandoon, the breeding site for this species is over 6 km along the Ayeyarwady River. The fish is found from May to June along the concrete of bridges; its size ranges from 1.5-2 inches. The fish is found breeding on the left bank of the river in June in Hinthada.

Figure 51: Breeding sites of Rita rita

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Wallago attu Distribution of Wallago attu Wallago attu thrives in fresh and brackish water. This species is demersal and potamodromous. The maximum length recorded is 240 cm; however, the common length is 75 cm. This species is usually found in Asia, including Pakistan, Viet Nam and Indonesia. This species is found in large rivers, lakes and tanks. It is a large, voracious and predatory catfish. This species is associated with deep, still or slow-flowing water with a mud or silt substrate. It is sluggish and stays on muddy or silty bottoms in search of food. The juveniles feed mainly on insects, while adults feed on smaller fish, crustaceans, and mollusks. It is destructive to other more valuable food-fishes. It is oviparous. It is abundant during the warm season and is a pre-monsoon summer breeder. It bites strongly if handled, with its huge mouth, formidable jaws, and band of conical teeth. This species is threatened due to over harvesting.

In the Central Dry Zone, Wallago attu is harvested in Myinmu and Pakokku Townships. This species is harvested in two seasons, the first between January and March and the second season is between November and December. Fish caught in this zone belong to three size classes: 10, 15 and 20 inches (25, 38 and 52 cm), the smaller size is caught in Pakokku between November and January of the coming year. Yield is highest in Myinmu during November at around 120 kg per day. When they find the species in their catch, fishers are not sure whether that species is migrating or not.

In the western part of the delta, Wallago attu is harvested in Ingapu, Thabaung, and Mawgyun during May, September, November and December. Fish caught are 10, 15 and 20 inches long (25, 38 and 52 cm); size is smaller in the northern part of this zone. Yield is highest in Ingapu during September at around 50 kg per day. Fishermen in Thabaung and Mawgyun observed migration of this species.

In the eastern part of the delta, Wallago attu is harvested in at least five townships (Kyangin, Myanaung, Zalun, Yandoon and Maubin). The first harvest season is between January and April, and the second harvest season is between September and December. It can be noted in the figure below that this species is found or is harvested in Yandoon for nine months between May and January. The species caught has a size of 10, 15, and 20 inches (25, 38 and 52 cm), and the smaller size is harvested in the northern part of this zone. Yield is highest in Kyangin during October and November at around 100 kg per day. When they find the species in their catch, fishers are not sure whether that species is migrating or not.

In the central part of the coastal zone in the delta, Wallago attu is harvested in Pyapon and Bogale during April, May, October and November. The size of this species harvested is 20 inches or 52 cm, which can be regarded as adult size. Yield is highest during October at 15 kg per day. Fishermen observed that this species is migrating in Pyapon during its occurrence.

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Table 9. Fishing gears used to catch Wallago attu

Habitat Type Habitat Name Gears Used Flood Plains Bogale River Drift nets Paddy Field Pyapon Township Drift nets Beach seine nets Drift nets Ayeyawaddy River Set gill nets Surrounding nets River Long lines Chindwin River Cast nets Nga Wann River Drift nets Toe River Long lines Yarzudaing River Trammel nets River Bank Pyapon River Drift nets Others Surrounding nets

Figure 52: Migration of Wallago attu in the Central Dry Zone

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Figure 53: Distribution of Wallago attu in the Central Dry Zone

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Figure 54: Migration of Wallago attu in the Ayeyarwady Delta

Figure 55: Distribution of Wallago attu in the Ayeyarwady Delta

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Breeding sites of Wallago attu Wallago attu’s breeding sites are located in many places including: Katha, Kalewa, Myinmu, Pakokku, Kyaik Hto, Kyangin, Myanaung, Ingapu, Thabaung, Hinthada, Maubin, Twantay, Mawgyun, Zalun, Yandoon, and Waw.

The breeding site in Mawgyun is the biggest, at the confluence of the Myngagon and Ayeyarwady Rivers. This 25 km-long area consists of sand beaches and floodplains.

Wallago attu is breeds in May-June in Myanaung along the Ayeyarwady River, at a site that is over 6 km long. The breeding site in Katha is over 10 km long in the floodplains and shallow waters along the Ayeyarwady River. The fish is found breeding in June and July. Around the same time, breeding in Pakokku takes place along the upper part of Ayeyarwady River over 6 km of floodplains. The breeding site in Hinthada is over 13 km long along the Ayeyarwady River. The site is on the left river bank in the floodplains. The spawning takes place in Kyaik Hto and Waw between May and June.

Figure 56: Breeding sites of Wallgo attu

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