FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person * WATTS GERARD J   2. Issuer Name and Ticker or Trading Symbol CYANOTECH CORP [CYAN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) COO (Last) (First) (Middle) 73-4460 QUEEN KAAHUMANU HWY #102 3. Date of Earliest Transaction (Month/Day/Year) 04/05/2018 (Street) KAILUA-KONA, HI 96740 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Cyanotech common stock 04/05/2018   M   57 A $ 0 57 D   Cyanotech common stock 04/05/2018   F(1)   22 D $ 5.25 35 D

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Cyanotech common stock options

$ 4.72

(2)

08/18/2024

Cyanotech common stock

45,000

45,000

D

Restricted stock units

(3)

04/05/2018

M

57

(4)

(4)

Cyanotech common stock

57

$ 0

113

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
WATTS GERARD J 73-4460 QUEEN KAAHUMANU HWY #102 KAILUA-KONA, HI 96740			COO

Signatures

/s/ Dan Sprague, by Power of Attorney		04/09/2018
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	The reporting person is reporting the withholding by the Issuer of 22 shares of common stock that vested on April 5, 2018 pursuant to the April 5, 2017 RSU grant, but that were not issued in order to satisfy the reporting person's tax withholding obligations in connection with the delivery of the converted common stock to the reporting person as of April 6, 2018.
(2)	Mr Watts acquired 45,000 stock options on 8/18/2014, of which 15,000 options became exercisable on 8/18/2015, 15,000 options became exercisable on 8/18/2016, and 15,000 options became exercisable on 8/18/2016.
(3)	Each restricted stock unit represents the contingent right to receive one (1) share of Cyanotech common stock.
(4)	The restricted stock units shall vest as to 57 shares on 4/5/2019 and 56 shares on 4/5/2020, in each case subject to continued service with Cyanotech on the vesting date.

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